One thing to do during long nights is night photography. Long exposures and light painting. Running around and waving a light frantically while shutter is open helps warm up.
To maximize the use of daylight during late season trips, I get up way before sunrise, eat breakfast in the dark, and start going half hour before sunrise, when it is quite bright. At least this is the intent - sometimes I end up late. Sleeping bag is usually a bit moist, and tent sometimes too, so I dry them out at a later stop. I find campsite around sunset. Sometimes later, usually unintentionally. Moonlight helps. So instead of spending time enjoying the campsite location, I stop mid day in nice spots on the way.