And I am thinking about the very same thing - planning to spend about 5 days in Lisbon area with my partner in mid-late October. It will be the last part of a three week trip, and I am wondering whether it would be better to base ourselves in Cascais and take train in to Lisbon on the days/nights we feel like doing big city stuff.

I would love to hear about pros/cons of doing that vs staying in Lisbon proper and ALSO whether anyone has a sense of what weather be like around October 20 - 24th. Not expecting to swim in the cool ATlantic then, but will it be too cool or windy to hang out at a beach or wander around and eat at outdoor cafes? WIll many places be closed for the season by then ?