15 nights in Portugal - help please!

There’s is so much to see and do in beautiful Portugal!
I’d urge you to get a hold of a couple of guidebooks to help you narrow down what you’d like to see & do in each of the cities you’d like to visit.

Do consider spending a couple of days in Sintra, at the beginning of your trip, and ending your trip in Lisbon.

Will you be traveling via public transportation, or do you plan to rent a car?

Enjoy planning your trip!

Edited to add... My daughter and I visited Portugal last year and this was our itinerary: Flew to Lisbon > train to Sintra> train to Évora > train to Tomar > train to Coimbra > train to Porto > train to Lisbon.

You are smart to skip the Algarve, IMO. The towns you mention all look good with the exception of Nazaré. It’s one of those places RS raves about that I don’t understand. Try googling ‘Silver Coast Portugal’ for lots of other places that would be better.
It’s still high tourist season, so I encourage you to go ahead with accommodation reservations soon.
As far as things to do in each place, any good guide book will give you lots of ideas. Trip Advisor also does a good job with top things to see in any destination.

I too don’t care for Nazaré. I stayed near Caldas da Rainha when I stayed in this area, which was a good base for exploring Obidos, Tomar, Alcobaca etc with a hire car.

Evora can be done as a day trip from Lisbon, just about, but is better with an overnight stay. Porto is compact and can be seen in a full day. The Douro can be seen as a day trip from Porto or an overnight stay.

Lisbon 4 nights

Evora 1 night

Caldas da Rainha area 6 nights

Porto/Douro 3 nights

Lisbon 1 night

First, some basics. Have you considered flying open-jaw, into Lisbon and out of Porto or vice versa? Would you consider renting a car for part of your trip?

Like Priscilla (in fact somewhat with Priscilla :-), I started in Sintra. It's one of the prettiest towns I visited and the sights are worth seeing. It's an inexpensive 30-40 minute Uber ride from the airport. I agree with Kathryn about Nazare, skip it. I hesitate, but what the heck, it's only an opinion . . . I was not impressed by Evora. I did not visit the monoliths (to each his own) but if you want to see them, Evora is the place to do it. I really liked Coimbra (2N, one full day). I used Tomar as a base (with a car) for 3N to visit the surrounds and it worked out well. I do think Jennifer is underrating Porto, but again, we all have our opinions. I spent 2N at a quinta in the Douro Valley - excellent.

Hi: Thanks to all who've replied thus far; the more help/info the better. I'll be booking our hotels/air bnb's this weekend. We'll be renting a car for sure. We've already booked flights. Flying in from Toronto; was significantly cheaper to fly in and out of Lisbon. From what I'm hearing we should go from airport to Sintra and then to Lisbon? Again, welcome as much info as possible including how long to stay in each location - knowing we don't want to be only 2 nights in each spot. Thanks!

Do I need a car to get around Sintra? Thinking maybe we uber from Lisbon airport to Sintra, stay 2 nights? Then off to Lisbon and rent a car when leaving Lisbon?

No
A car in Sintra would be a pain in the neck
There are taxis and tuk tuks and Uber and the bus

We plan to do just what you propose
2 nights in Sintra then to Lisbon
We’ll pick up car as we leave Lisbon

Since you have a RT Lisbon, go to Sintra first then wherever next- pick up car as you leave Sintra
End in Lisbon so your nights there are not split

Yes, start in Sintra without a car. Check rental rates. Instead of renting in Sintra, it may be cheaper to Uber to Lisbon (either Oriente train station or airport) to get a car and do a loop ending with all your Lisbon nights together. Consider going north by car from Evora to the Douro Valley and dropping the car in Porto, then using the train for other points on the way south to Lisbon. You will not want a car in Porto or Lisbon, and you can easily visit Aveiro (optional) and Coimbra (lovely) by train.

How long should we stay in Sintra? 2 nights? 3 nights? We land at 7:30 am Lisbon so first day we may be a bit tired. Thought we may do hop on/off first day in Sintra. Thoughts please. Thx!