Flying out this Sat! Are reservations for nicer places in the evening recommended?

this is low season so rsvp shouldn't be necessary. What you'll have to worry about is what may be closed in low season. If you look at websites they may note when they'll be closed. I know Pineapple Pete posted here that their place will be open all year.

I recommend them. Restaurants appreciate the heads up and generally reward reservation holders with better tables.

This time of year, you don't need them at all..