When I visited in October we just walked in and got tickets and it wasn't crowded at all. I don't think there are many tourists in Salerno and many of those are passing through rather than touristing. And in November with the AC closed I can't imagine it will be busier.
As I recall the only odd thing was that the ticket came with an additional religious site in town so you had to choose which other sight you wanted to see. I didn't really want a combo ticket and we struggled a little bit with my Italian and their English until I figured out it wasn't optional. I think this was tied to the restoration funds for other places so they were attaching them to the "big ticket" church.
Hopefully you'll get to see the lights on in November in Salerno, enjoy,
=Tod