1.) If you are considering a visit to Sintra, a day trip is not enough!! We stayed three nights, and it was perfect for what we wanted to see and do.
2.) Stay at Burghard’s! This apartment was close to historic center, but on a very quiet street. It was so clean!! We did not use kitchen much except for coffee, but it seemed adequate. Burghard’s wife met us to check us in, and she was so helpful and welcoming. We really appreciated the local tips!
Note: Sintra is quite hilly, and there are some steps and uphill/downhill requires to get to the apartment. We walked maybe 20 min from the train station, and it wasn’t bad.