Thick comforters for sleeping! Or just take a sleeping bag and open it up to use as a comforter. Personally, I love sleeping in a cool to cold camper. Wake up in the morning, start the percolator coffee maker on the stove, and camper warms right up. Or - you can do hot water for tea or hot chocolate!
On our TT, the furnace fan seems to use more power than the vent fan in the bathroom - or is just less efficient, not sure which (or maybe both).
Remember to crack window(s) and roof vent open a bit for venting!! Don't seal up the camper - venting will cut down on condensation, and will give you some fresh air.