In spite of the comments from others attesting that flannel curtains will be fine in the sometimes damp environment of the Scamp
interior, I have my doubts. We have experienced dampness which resulted in our comforter being dampish and clammy. It has been difficult to dry our comforter and towels. Our solution is to carry Damp-Rid from now on, spread out the comforters to dry during the day and to use small, lesser quality towels or backpacking towels that dry more readily. You'll notice that the Scamp
factory - installed curtains are of 100% synthetic, much like some shower curtains.
That said, I would always choose the fabric design that I love over practicality. I like to vary the look and theme of my Scamp
and I do that by sewing 10" wide print panels that I put on each end of the rods with the original curtain in the middle. I make 16" pillows to match. I use cotton or cotton blend fabrics because I love the prints. You'll notice, too, that I made tie-backs that "adhere" to the "rat fur" with Velcro. (Just a tip: hook and loop tape, aka Velcro, costs only $1 per 1 yard hank at JoAnns. Ask for it because they do not keep it with the expensive Velcro brand)
See the photos below showing my black-out shades which are attached to the "rat fur" with Velcro. I suggest sewing a few 3" lengths along the bottom edge with long spaces between. The Velcro secures to the rat fur very tightly and you will want to remove the shade easily. The exception is for the window at your head while sleeping. There you need to have one long seamless strip of Velcro to prevent cold air from seeping down on your head.
I have tried to use magnets on my 2011 Scamp window frames and find they do not "stick". I think the frames are aluminum.