Sintra-Lisbon-Porto 10 nights - Opinions on rough itinerary

Abby & Cody, I think your plan sounds basically great.
I would recommend 2 nights in Sintra to start, for 3 reasons. First, Sintra is wonderful, with various very nice sites, which can easily take a half day each, plus a nice town with some fine restaurants and bakeries. Second 1-night stays are not very satisfying or relaxing. And three, given possible jet lag, your arrival day might be limited. I can recommend a very nice and affordable B & B and one or more great restaurants if you like. I think the idea of an Uber directly from the airport to your front door in Sintra is a great one, as long as there is Uber in Portugal, I never used Uber there.
Then 4 nights in each of Lisbon and Porto would be great. Various interesting sites In Lisbon, and old neighborhoods to wander around. Porto has fewer sites, but has those many port wineries and tasting rooms across the river,. A day trip up the Douro, by boat, train or bus, maybe some combination, would be great. Maybe shop for a day-long tour that combines scenery, wine estates, great lunch, etc. I think a good tour going at least one way by boat would be ideal.
Enjoy beautiful Portugal!

Avoid going into Lisbon in morning rush hour. That probably means leaving Sintra around 9.00-9.30 am or on a weekend.

You are better off going right to Sintra, then Lisbon, then Porto.

A relatively new mode of transport from Sintra to Porto might be helpful. There is now an express bus from Cascais that stops briefly in Sintra before heading non-stop to Porto. If you start in Lisbon then spend a night or two in Sintra, you can easily go from Sintra to Porto without having to trek back into Lisbon to catch the train.

I personally think only three nights in Lisbon isn’t enough. With your limited time frame, you might want to just day trip to Sintra. But, full disclosure here - I’m one of the big minority that doesn’t care for Sintra. With the bus, though, you could go to Sintra very early, spend one night then bus to Porto.

If you like wandering around neighborhoods, Lisbon and, to a lesser extent, Porto are made for that. In Porto, don’t forget the Gaia neighborhood across the river. The port lodges, some of which have regular wine tastings, too - is a delightful way to spend an afternoon.

Thanks for the help. We will do 2nt Sintra- 4nt Lisbon - 4nt Porto. Either way we would probably have to shortchange one of the cities and Lisbon is probably the easiest to return too when we fall in love with Portugal.

Larry - We would very much appreciate any recommendations - particularly accommodations in Sintra. I thought we had plenty of time to book but when I went to book the InPatio guesthouse in Porto I had to slightly adjust travel dates since they were already booked up 7 months in advance.

We are doing a similar itinerary at the end of next month, but going to Sintra>Lisbon>Algarve>Porto. Our flight arrives in Lisbon earlier than yours (5:30 am) so we will uber to Sintra and stay one night, planning to explore the sights over our first full day and 2d partial day there. I chose Sintra1012 Guesthouse, which gets great reviews, seems optimally situated, and is extremely reasonable- I'll be happy to report back in April! I actually booked 2 nights because it's so reasonable, although we'll sleep there overnight only one, so that we can check into our booked room as soon as we arrive, enjoy their included breakfast and/or nap before heading out. Happy planning!

The InPatio Guesthouse in Porto is the best B&B ever. Book it way ahead of time, it only has five rooms.

Two nights in Porto would be a minimum, and you can either take a short cruise up the Douro River, or take the train (runs on the North riverbank) up river and stay a night or to in one of the smaller cities like Regua.

On Booking.com there are a number of inns in Sintra that are highly rated by past guests. I stayed at Chalet Saudade, a quaint inn, and enjoyed it very much. It is well-located, about mid-way between the train station and the center of town, easily walkable in each direction, lots of art on the way into town. . The owner/manager is totally bi-cultural, I think she was born, raised and educated in the US, part of a Portuguese family, then re-located to Sintra as an adult. I think I have that right. She and the staff were very friendly and helpful. There was a comfortable living room for guests to enjoy, and when I was there, there was always a decanter of Port in the living room for everyone’s pleasure. The same family owns and operates the nearby Cafe Saudade, and inn guests are given a voucher for a complete and delicious breakfast served at the cafe. (note: in Portuguese, “Saudade” means “longing” or “missing”.)
An excellent nearby restaurant is called Incomum ( = “uncommon”) for either lunch or dinner, reservations are a good idea, as it’s a popular place.
There are several major sites in Sintra. I especially enjoyed the Quinta da Regaleira, and the Pena Palace including a tour of the beautiful grounds. Also, poking around the town itself, with some excellent shops and bakeries. The National Palace in town is an interesting building, visible from all over; I did not go inside myself, but heard that is also a highlight
Enjoy beautiful and very friendly Sintra!