I too, stashed my PW curtains.
they are fiddley and hang down in line with the dash board
I cut a piece of reflectix which covers the windshield and use the visors to hold in place ( other pieces cut for door windows and the doors closed on them) this gives a bit more space and if the seat is rotated it's not snagging
I do have the exterior cover and use for multi-day camping
you can get shower curtain at home store and find the roller clips which attach to the rail ( if you don't have) and make one.
i'm not sure if these roller clips are the correct size, but you get the idea
https://www.amazon.com/RV-Designer-A...s%2C327&sr=8-3
my shower curtain is stashed as well, we don;t shower inside. we are either in a campground and paying them for water and energy to heat it ( wear flip flops) or we are in the boonies and use the out door shower wand
mike