We are planning a 12-14 day trip to Prague and Budapest. I have found airfare that allows us to fly in to Prague and out of Budapest. A woman I know who lived in Munich thinks 4 days in each city is enough time for each. Since we have a little more time left should we add on some other places or is the 4 day allotment too short? Any suggestions?

Include Vienna it fits in nicely after Prague and before Budpapest.

Definitely put Cesky Krumlov on your list. Can be a day trip from Prague, but worth an overnight stay. A World Heritage site. Small medieval town, totally walkable, charming atmosphere, wonderful architecture, great restaurants. Well worth the visit.

Be sure to see the "bone church" in Kutna Hora outside Prague. Just a small day (or half day) trip.

Thank you all for your responses. I will research the latter 2 areas mentioned. I know Vienna is in line geographically with Prague and Budapest, but I've heard it is very large and doesn't have as much to offer. We visited Salzberg 2 years ago and loved it. Any more thoughts on Vienna?

I think there are a few things worth a visit in Vienna.
But maybe you could give a few examples of your likes or dislikes so it would become more obvious why you think you'll like Budapest but are afraid that you won't find Vienna interesting?

I think our image of Vienna is that it is a very large city in comparison to the other 2 we have chosen. I read a few threads today relating to Vienna and it appears most people do enjoy their visit. My husband and I both enjoy visiting museums, churches, historical landmarks, etc. when we travel. We think being in places where you can mix in with the people and culture is also fun. Of course I love some shopping and my husband is sweet enough to tag along, as long as we agree on the amount of time allotted. I think I would enjoy the musical opportunities, but I don't think my husband would be as thrilled. We don't want to spend lots of time on trains between cities and sometimes flights are an option but can be cost prohibitive as well.
We've come up with a tentative itinerary and would appreciate feedback from anyone willing to take a look:

September 24 US to Prague

September 25-29 Prague

September 29 - Oct. 1 Vienna (arrive by train)

Oct. 2-6 Budapest (train in on 2nd)

Oct. 7 Return to US

Cesky Krulov sounds interesting, so we might want to somehow add that in to our time, but we're not sure.

Please feel free to comment on any aspect of the trip. I'm beginning to read about accommodations in these cities, so any thoughts on those would also be appreciated. Thanks everyone!

Thanks for the update.

Vienna may be larger in size, but most interesting sights are packed in or on the edge of the 1st district: the Austro-Hungarian Empire buildings (palaces, opera, also museums - on the ring road which goes around the 1st district), the Cathedral and also the major shopping area.
The only major sight I can think of which will require a subway ride would be Schönbrunn Palace, but even that is not far away (15 or 20min). Or a short tram ride to the Prater to ride the ferris wheel.

The historic center in Vienna is plenty compact. I recently spent six nights in both Vienna and Budapest on second visits, so I'd say there's more than enough to keep you occupied in both places for more than four days. (Trip report at fodors.com/forums/threadselect.jsp?fid=2&tid=35096856)

Forget the Ferris wheel; seen one, seen all. Yes, it's bigger, but it's slower; with about 24 cars (each the size of a cable car, taking about 5 minutes each to go from 12:00 to 12:30, so to speak, I'd rather watch a golf match).

If you like art, you can't beat the Kunsthistoriche Museum. It made a convert of me. The Treasury (of the Hapsburgs) was also nearby, and fascinating. Hugest ruby I've ever seen.

Worth 2 days, not 1 as your itinerary calls for.

Ok...sounds like there is plenty for us to see in Vienna so we can add on another day. So does anyone have recommendations of places to stay that are in the hub of things? I prefer a hotel with a lift and will we need AC at that time of the year? Where we live in the US can be quite hot at that time of the year. We were in Munich and Salzberg about 2 years ago at this same time and we experienced a wide variation of temps during the time we were there. We like nice places, but lodgings don't have to be luxurious. (three and four stars are good, unless we can find a great deal on a 5 star) I don't think the Euro applies in Prague or Budapest? It's nice to have a place that either serves breakfast as part of your fee or there is a coffee (like Starbucks) shop nearby. Look forward to your recs--thanks.

You are right, Czech and Hungary have not joined the Euro zone, yet.
Though you will find zillions of ATMs everywhere to withdraw the local currency. Some stores in Budapest also take Euros, so you can spend any you may have left from Vienna - at a not so favorable exchange rate, usually.

Climate can still be pretty warm, especially in Budapest. It may just be 75F as well, but that is hard to anticipate.

Day trips from Budapest:

- Szentendre, cute little town North of Budapest. Cobblestone streets, antique/souvenir shops of all kind. Tourist-oriented, but not overly tacky.

- Gödöllö, Empress Sisis palace (or manor), NE of Budapest

Both sights can be reached by regular and inexpensive suburban trains from Budapest.

It can be assumed that your hotel will also have numerous leaflets in the lobby advertising all kinds of day trips, from Danube cruises to Esztergom abbey to day trips to the Puszta.

For travels within the city you will have to check, if a 1- or 2-day-Budapest Card (which also includes free entry to museums or a discount to other places) is what you want, or if a regular 1-, 3-, or 7-day-travelcard (just for metro, tram, bus, etc) is better for you. Or a coupon book with 10 single tickets which you can use as you need them.

Thank you for side trip ideas and info for getting around the cities. So much can be learned on this forum! Any ideas where to stay?

Vienna and Budapest are the same size. No problem with being overwhelmed by Vienna -- it's manageable, indeed supremely efficient and visitor-friendly. Esp city transport.

By visiting these 3 cities, you will visit the 3 historical capitals of the old empire. Yes, Prague was once the capital -- briefly, in the 1500s. So it's the perfect trio for a visit.