Regular sheets, knit cotton blanket, and down comforter. I keep the thermostat set at 62 to 65 during the day and turn it all the way down (or sometimes off) at night.
We use a heated mattress pad at home to warm the bed up in winter, but turn it off when we go to bed.
In the RV, things warm up soon enough once we get in bed. No heated pad/blanket. The mattress and mattress pad are more than enough to keep heat from escaping from below.
Wayne