Before we went to Alaska, Yukon and N.W.T. we made blackout curtains for all the windows. We just hung them with velcro. We bought self adhesive velcro at the dollar store and stuck pieces to the valance or window frame and corresponding pieces to the fabric. Put up at night , take down in morning.
Using this idea we can let some light and air in through the lower windows. I also installed a black vent cover over the vent over the bed, it keeps out most of the light and allows air to circulate.
We still use them 4 years later.
I am assuming that you mean a curtain across the entry to the bed area from the main part of the camper. Putting a curtain across there cuts down on air flow, so no air circulation from the furnace, if needed.
Brian
