Pictures of my window curtains but I think both would work well for windows or a door

For daytime my curtains are a thin gauze weight cotton sheer that allows lots of light to come through but people can't see through. They hang over simple wooden dowels.

At night I part the sheers and velcro (with four tabs) black fleece curtains straight over the same rod the sheers hang from. They block out almost all of the light so even when the lights are on inside of the trailer you can't or can barely tell from outside. One of the nice things about fleece is you don't have to sew/finish the edges. Very similar to felt in that the raw edges won't fray. If you're curious to see how the velcro attaches let me know and I can take additional pictures. I just fold them away during the daytime.

I also made an additional curtain out of mosquito net to cover my door when I want the ventilation but not the bugs that come with it.
Not a great picture but an idea of how the mosquito net curtain worked inside the door with my pup sleeping outside. I attached it with a long strip of grey, industrial strength velcro along the top (hooks on the trailer, loops on the curtain to prevent snagging), two short strips at the mid-point on each side, and tucked the bottom under the mattress.
