Booked my ticket that gets me to Lisbon in the morning of Nov 12 and flies out from Porto in the morning of Nov 27. This leaves me 15 nights in the country. I prefer going places by train (complimented by bus) and am interested in arts, cultural and historic/religious sights. Other than the two main cities, my research leads me to believe I would want to visit Sintra/Coimbra/Évora/Tomar/Batalha/Obidos. The thing I am not sure is how much time to spend visiting Algarve given the season. Also any general advice on how to arrange my days and overnight stays would be greatly appreciated. Thank you!
It looks like you’ve got at least enough to do in that time frame without visiting the Algarve, So I’d skip it.
Skip the Algarve. Even though taking the train down there is easy, it would take up a good portion of two days.
You could divide your time fairly evenly between Lisbon and Porto with a night or two in Coimbra. From Lisbon, you can visit Evora, Sintra and possibly Obidos by bus. I personally would skip it. You might want to check bus schedules to Tomar and Batalha. I prefer Alcobaça to Batalha but both will be a bit trickier to access on the bus or train.
You didn’t mention any smaller places in the north, but Braga and the Douro are very easy from Porto.
Thank you everyone for your valuable inputs! :)