That's a really broad question, but to get you started in your research, Andalucia would be an obvious choice, especially since you mentioned nature. There are many posts here about the region.
I see no need for any rail pass.

We need more information about you and your interests as well as some idea of what you are hoping to do and see in Spain if we are to be at all helpful. Are you looking for art, museums, dance, hiking, guided tours, beaches, history, architecture, etc. What is your budget? Do you have a lodging preference? Have you looked at any of the information already posted here about Spain? You can search by country at the View by country link above or in the Search the Forums box above and to the right on your screen. Please post again and ask for more specific information. We'd love for you to have a great trip!

When our family of 3 was planning our trip we used advice from here, tripadvisor, Rick Steve's (we did look at other books too but his was the most practical) and Maribel. We planned around flights we were able to get because we had to book way in advance in order to use frequent flyer miles. We were glad we tried to spend 3 nights in each main city but that was us. We also did not want to drive. We took trains and metros. Got taxis from trains to hotels. Decide a route first if you can,deciding if you will rent a car because that will make a difference. Research rental car rates but call because info obtained here and from books were incorrect so call direct.

The Indiancouple posted a great trip report here awhile back. They were very thorough and I took alot of information from that for our trip to Spain in March/April 2009. We landed in Madrid exhausted from an overseas flight, explored Madrid, did a day trip to Toledo (5 nights total), then took the AVE to Seville (4 nights), awesome, picked up a car and drove to Jerez de la Frontera for two nights, then to Granada for three, onto Malaga for 3 more nights and three in London before heading home. If I had my time back I would have added one more day to Madrid because I did not see all the art nor churches planned and would have traveled to Segovia for a day. I would have also added another day to Seville, it was magical - you may want to add a day or two in one of the White Villages. Enjoy - Spain is very regal.

seeing your daughter is 26 then maybe she wants to go clubbing then go to Ibiza...sorry what are your interests?

Our daughter was 22 and was happy to do what we did which was to get up early and sightsee and turn in early. The kids told us they partied until 4 am slept in and did the same the next day. The tour groups we saw (especially in Sevilla) that had college students, looked like the kids had been up all night as they yawned and looked bored at the historical places.

We had been to Barcelona so we did, 3 days in Madrid (one day trip to Toledo), 1 night in Cordoba (glad we did it, glad it was only 1 day), 3 days in Granada, 3 days in Sevilla and 3 days in Lisbon (one to Sintra).

Lisbon was hard to arrange so we wound up with not cheap flights but we were really glad we did this.

Really glad for preplanning and for pre-arranging the Prado museum in Madrid and the Alhambra in Granada. One of our favorite places was the Mesquita in Cordoba. On of the things we could have skipped was the white village tours out of Sevilla.

Glad we did Flaminco show in Sevilla, glad we did a Fado show in Lisbon.

You will really enjoy your trip.

dchal09 writes: "My daughter, 26 and I are planning 2-3 weeks in Spain next June with maybe a week in Morocco. Where should we concentrate our travels to? Is it better to get a Eurail pass or just buy rail passes as we go? We love nature as well as city life. Any suggestions would help us plan. "

Last question first: There's a SpainPass (Spain only) and an IbericPass (Spain & Portugal) that costs a bit more. And there's a FEVE (Ferrocaril Español de Via Estrecha) 30-day pass (hop on, hop off) for its routes across Northern Spain. But I don't know if I would buy any type of RailPass because I get along fine with MotorCoach (Bus) Service: No added cost for seat reservations; more frequent & direct service.

Do you have a compelling reason for visiting Morocco? If not, or if only to tell friends you have been to Africa, forget it!

If this is your (or daughter's) first visit to Spain, you'll want to visit Moorish Spain with its monuments, gardens and Mosques (Granada, for example); but after Cordoba, Sevilla, Granada and Toledo, I would head North.

I love Northern Spain, particularly Cantabria & Galicia. the Principality of Asturias, nestled between the two, is also OK. Do a part of the Pilgrimage to Santiago de compostela where Apostle James' Remains are interred

Thank you so much everyone. I'm thinking now of starting in Madrid with side trips to Toledo or Segovia, taking the train to Seville, then Cordoba, then Granada, then Barcelona. From Barcelona I'll return to Madrid, and then rent a car for northern Spain. Is that all doable in 3 weeks? If I have to cancel something, I'd prefer to delete anything too touristy. I love remote authentic villages, art & culture and of course beautiful nature.

It really helps to write it all out in a list to see if you can do it in the time allotted:
Madrid
Madrid
Madrid (Toledo or Segovia day trip)
Madrid
Sevilla (you could stop in Cordoba en route or do a day trip)
Sevilla
Sevilla
1 week
Sevilla
Granada (maybe some day trips while in Granada)
Granada
Granada
BCN
BCN
BCN
BCN
2 week point
BCN to MAD
last week exploring northern Spain

I'd say it works, but of course most of the first 2 weeks are touristy--no getting around that. But that isn't necessarily a bad thing--they are touristed for a reason.
You could of course reduce the number of days, but I recommended a leisurely enough pace that allows for transportation, etc.
You can try to get your nature and villages in the north, or add more time elsewhere for more rural explorations.

Denise and Yorkshire have great ideas. You will probably find Madrid, Seville and Granada to be your favorite places. I would cut out Barcelona and and spend some time in Cadiz, Jerez, Arcos, Ronda or Malaga and northern Spain. Seville deserves 3 nights and 4 is even better, Granada deserves 2 and 3 is even better. We just retruned from Barcelona and San Sebastian. If I could do it over I would skip Barcelona and spend 10 days in San Sebastian, Asturias and Galicia they are really special places. Now for Morocco if you can fly into Marrakesh and spend a few days there and Essouira that's one thing. If you plan on taking a ferry to Tangier I would really advise you to skip that. Come to think of it Marrakesh is fascinating and Essouira is groovy but I would much rather spend all of my time in Spain. I've been to Morocco twice and each time I got back I wanted to kiss the ground in Spain I was so happy to be back.

Yes, Thank you for all the great ideas and pointers. I am still fine tuning my itinerary. I found the bus is so much cheaper and plan to take the bus to Cordoba from Madrid, bus to seville, bus to Granada, and then the train or fly back to Madrid to hit the North. Is it better to rent a car to see San Sebastian, Asturias, Galicia? Is a week enough time? I am cancelling Barcelona and Morocco as many have suggested. Does the bus get you to Jerezs de la Frontera or Arcos de la Frontera or do you need to rent a car?

I feel glad for you that you are spending more time in Andalucia. Mixing in smaller towns between cities will make for a wonderful trip.
Buses to Jerez are very frequent, to Arcos as well I believe (but not sure of day trip feasibility). You only need a car when you must dictate your own pace and want to see smaller towns as day trips or do more hiking, etc.
I was in Jerez on a Sunday and it was so quiet I felt I was in a ghost town--but I think it would be pleasant on a more lively day. Arcos looks amazing, but it might not offer much more than looks based on heresay--I only passed by in the bus.

The bus gets you everywhere in Spain and for some strange reason is much more bearable than the bus in the States. I know it's a lot cheaper than the high speed train but it is a lot longer, the train is so fast and relatively comfortable. I would definitely bus to Granada and from there to Madrid it's a 4-5 hr. bus ride. AVE train connects Malaga to Madrid so you could spend a night there. I would say it's better to rent a car for the North coast as it's easier to get into La Rioja and the Picos de Europa and places like that, the problem I find is that the prices are off the charts for car rental in Northern spain compared to Andalucia. Again the train and bus system along the North coast are great. I would say a week is not enough time but it could be done. It takes us 5 days to get out of San Sebastian alone it's so nice. Remember to read Maribelsguides.com.

I would like to echo Nedshireland's comments on Morocco - skip it. It will consume a lot of time getting there and once there what you will see are trashy tourist markets, and getting there is not cheap.

We just returned on Monday from Spain and spent most of our time in Madrid and Galicia. Spain is about the size of Texas, which is handy to keep in mind when planning your travel. It is 6 hours from Madrid to Galicia and you are traveling through the desert and plains. The roads are great and put the roads in the US to shame. But once in Galacia, while the roads are in great shape you are in the mountains and the roads are very windy, and getting anywhere takes time. The beaches are beautiful, the towns are old and very traditional, and you think you are in another world. It is a beautiful part of the country. I am not sure that you can do Madrid, Galicia/Andalucia, Granada and really see anything in 2weeks. We had a car but there was bus and rail service to even the remotest towns.

This past spring we traveled to Morocco and Spain. I would go back to Malaga and Valencia any time...they had great charm, awesome architecture and history without the big city feel of Barcelona, not to mention the pickpockets there!

I would suggest that you read for yourself about Spain. And I would also suggest not to use Rick Steve's. Someone gave me his guide as what they thought was a gift. It is simplistic and filled with odd observations. Take a look at Cadogan, Michelin Green, and Rough Guides for sights and details and Fodor's and Frommwer's for restaurants and hotels.

We have spent a great deal of time in Spain and I would include Barcelona.

Planning our trip we used many books and many websites. Entering museums or finding other practical information we wound up using Rick Steve's and were very glad we did. My daughter and I read them as we went in places. My husband did not like Rick STeve's on principal but wound up asking us questions, looking at it the night before we went somewhere and then giving in and using it too.

One thing you need to be aware of is that most of Spain (except the Atlantic cost) and especially the south are VERY hot in summer. In Andalusia it's often over 100 degrees during the day. So whatever arragengements you make be sure that you hotels have good AC (some modest ones have none) and good pools - since it may be too hot in the afternoon to do much sightseeing.

Be have done 3 extended trips through Spain and Portugal - and always do them by car - since it makes exploring small villages much more feasible. Also we generally do late April,early May - which is plenty warm enough for the beach on the Costa del Sol.

Our favorite areas are Andalusia, Barcelona and the Atlantic coast. Madrid is not a favorite - since it's primarily a very modern looking business city packed with grey skyscrapers - looks more like Chicago IMHO than a different culture.

Also - be sure to consider some of the smaller places. We adored Merida (roman ruins) and Ubeda (a a cathedral with beautiful plaza and charming parador.