My wife and I, late 60’s, reasonably fit, have 12 nights in Portugal late May through early June. Flying in and out of Lisbon. So far we have 3 nights Lisbon followed by 4 nights Porto via train. We will spoke out for day excursions from those hubs to places like Sintra, Braga, Douro Valley. After Porto I’m not sure if returning via train to Coimbra and Tomar are best, or taking another route closer to the coast for Fatima and Obidos? Need to end final night 12 in Lisbon. Suggestions appreciated.
Lisbon is worthy of more than three nights - especially if "day excursions" are being considered from there. Evora is a recommended day excursion.
I agree that Lisbon deserves more than 3 nights. We spent 5 nights in Lisbon, including a day trip to Sintra, and I wish we had an extra night in Lisbon. If you like castles, there are a lot of interesting castles and palaces to see in Sintra so I recommend spending 2 nights in Sintra. That is what I wish we did. Seeing Sintra as a daytrip is better than not seeing it at all but I think the best way to see Sintra is to spend a couple nights there.
Coimbra and Tomar are much more interesting than Fátima and Obidos. While Obidos is quite cute it’s overrun by tourists and quite small. Both Coimbra and Tomar have significantly more to see and are easier to walk around due to fewer tourists. If you are not planning on stopping in these towns, the train will be much quicker with the Coimbra route.