Hi Dennis,
November is a mixed bag, as the more rainy season is in force. But, you are correct in that the tourist hordes are gone for the most part. But be aware, I still see tour buses in Cascais year round now. But, they are much less and usually just the mornings. The restaurants are easy to access without reservations and I mostly feel the town is locals.
Temps are still pretty good, with some cooler days and the nights are more chilly. But, I generally think of the cold weather arriving in December and especially January. Cooler is relative, though. No freezing weather, snow or ice all winter. Highs in the low to mid sixties a lot of days and the sunny days are clear and beautiful.
One thing to be aware of when looking for an apartment to rent is heat. A lot of older places don’t have heat (I don’t), which takes some adjusting. They will likely have space heaters of some sort at a minimum. But, with space heaters one usually heats the room they are in and the rest of the house is pretty cool. Central heat is really mini splits or radiator type.
It would be interesting to hear from people who have visited that time of year.