Hi Foderites,
I'm after recommendations on stops from Porto to Sintra.
I have 17 days in Portugal.
Fly into Porto - 3 nights,
Douro valley 3 nights,
Then finish with 2 nights Sintra and 3 nights Lisbon.
That leaves 6 nights to drive from Douro Valley to Sintra.
I had planned to stay in Aveiro (2), Coimbre (2) and Obidos(2), but after reading some trip reports, I've now gone off Obidos.
How would you best recommend my 6 days from Douro Valley to Sintra? Trying to avoid any single night stays and any days of too many hours driving. Tomar? Ericeira?
Thanks so much

We spent two nights in Evora and one night in Batalha. Loved Evora to see the Roman ruins, the Cathedral, the Chapel of Bones and the University. Also a major foodie destination. Really enjoyed our stay in Batalha and we stayed there primarily to see the amazing monastery. Many people stay overnight in Coimbre but we only stopped for an afternoon en route to Porto from Batalha. We also stopped at Aviero and I would have liked more time there as very pleasant.

Some people stay at Cascais, another place in which we only had an afternoon stop. We did also stop at Obidos for a walk and some lunch and personally I don't think I would overnight there.

Although not a direct route, I would highly recommend Evora as a worthy destination.

An enthusiastic yes! to Coimbra -- you might even want more than 2 nights there. I enjoyed Tomar, but one night was more than enough for me. Similarly, I enjoyed Aveiro, but a part of a day worked for my interests. A place from which you can easily visit the Batalha and Alcobaca Monasteries would be worth considering. Will 3 nights in Lisbon be enough for you? It wouldn't have been for me.

Another vote for Evora -- though as Madam397 notes, it's a bit off your path and you might have better options for this particular trip

If you don't already have it, I strongly recommend the Michelin Green guide for Portugal.

It's a wonderful country -- enjoy!

Since you've asked about places to stay on the direct route from the Douro Valley to Sintra. The Alentejo would be a detour, although a worthy one, and in fact, progol and melnq8 included the Alentejo in their itinerary coming from the north- you may want to check their trip reports.
In addition to Coimbra, where you could spend 2 or even 3 nights, you might seriously consider 2 or even 3 nights in Tomar, 3 nights would give you ample time to visit the Convento de Cristo, the tiny synagogue, to day trip to Alcobaça and/or Batalha, or even to visit the Aqueduct dos Pegões or the Templar site, the castle of Almoural, on an island.
We stayed for just 2 nights in Tomar and wish we had added a third. But.... we have friends who live there.

I love Coimbra and we spent happy nights there at the Quinta das Lagrimas, across the river, with an easy in-and-out and private parking. In addition to the tour of the university, its chapel and its library, it offers many more sites, including 2 cathedrals, a botanical garden, the wonderful Museu Nacional Machado de Castro (plan on 2 hours), places to experience the unique fado of Coimbra and just a short drive away, the Roman ruins and antiquities museum of Conímbriga, very worth one's time.

I wouldn't suggest overnights in Aveiro, as i think it's fine for a quick day trip, but can be seen in a few hours. The "Venice of Portugal" label, in imo, is somewhat of a stretch.
I'm glad you have discounted Obidos, as it's become extremely touristy these days and again, can be seen in a few hours.

Ericeira is lovely and has become a very up market and very picturesque beach and surfing town, it that appeals and is just a short drive north from Lisbon. If atmospheric beach/surfing towns appeal, it might also be a contender for 2 nights, but no major historic sites there, just a happy place to sit back and relax and it doesn't make as good a base for Tomar, Alcobaça and Batalha, as it's further south.

But speaking of relaxing, we also love very manicured, very relaxing and beautiful Cascais at the ocean and have stayed happily several times to relax and unwind after a long touring trip. But it's just short hop (40-minutes) on the bus or even quicker via an Uber/Bolt from Sintra.
Most visitors choose either Cascais OR Sintra and commute from either.

And I agree with kja about the Michelin Guide to Portugal. Invaluable. But i personally find the Moon guide to be not particularly well researched, so I would also suggest the Lonely Planet. I have all the Portugal guides in my library.
For an extended (not just 2 nights) visit to the site-rich Alentejo, the second edition of the Bradt guide by Alex Robinson is also invaluable, especially for a lengthy visit.

Thankyou all for your great responses. I'm somewhat limited by the 17 days in Portugal, Arriving in Porto and flying out of Lisbon.
Evora sounds wonderful from the trip reports I've read here, especially as we are foodies, but it just seems out of the way, unless I were to forego the Douro valley.
Porto, Sintra and Lisbon are my 'must stays', so I'm needing to decide on the middle section. Hubby has requested a visit to Nazare, but I've read the big waves are mainly present in Winter? We will be visiting in Autumn. But I guess that request has been steering me towards the coast. (Unless I can convince him it's not that worthwhile?)

Nazaré's big waves occur in winter and they're unpredictable. If your husband does want to see a lovely (and prettier to my eyes) fishing/surfing town, you could make a detour to Ericeira, which sits slightly below, south of the Silver Coast. And during this detour visit the palace of Mafra. The two are only 10 minutes apart.
But to decide if it's worth the detour, you may want to browse through Julie Dawn Fox's guide to this very up-and-coming town.

Although Fodorites progol and melnq8 did include Evora in their itineraries, either going up to or coming down from Porto/Douro, their trips were a bit longer than yours, not 17 days.

I only spent one night in Nazare and did not see the big waves. I found it a convenient places for Obidos and for the Alcobaca and Batalha Monasteries. I greatly enjoyed a long sunset walk along the beach. I know some Fodorites were disappointed in Nazare, and maybe I would have been had I stayed longer, but for my purposes, it worked well.

Our trip was 10 days in total and what we did was land in Lisbon and pick up rental car and head directly to Evora for two nights, then a long day of driving, first north to Castel de Vide and Marvao and then west to Batalha, then up to Coimbra, Aveiro and Porto before driving back down to stop at Alcobaca and Obidos before returning rental car and heading back to Lisbon. In Lisbon we did a tour that went to Sintra, Cascais and westernmost part of continental Europe. It was a good tour but in retrospect I would have not gone all the way to Marvao. We also did a day trip from Porto to Guimares. I think that this trip was in June of 2018 as it was during the World Cup and very festive in Lisbon with giant screens in the Praca and everyone walking around with flags and painted faces. Unknown to us our trip to Porto fell during an annual festival that involved people walking around bopping each other on the head with plastic hammers. In fact our hotel gave us our own plastic hammers. Very festive, lots of balloons that were lighted and floating around and huge crowds roaming around, fireworks, music festival. Unfortunately, Porto looked the worse for wear the next day with smashed party hats and water bottles all over the place but it did get cleaned up quickly.