Learned this when I was in the CG on a ship without a lot of space. Bought 4 travel toothbrush holders, put the soft side of velcro on the holder, and the rough side on the wall, take off when you need to use the travel holder. You don't have to worry about it falling while driving either! Our toothbrushes don't fit in the mount that came with the trailer, so we never mounted it.
Side curtains hang on bungee cords strung between hand holds. Front curtain is on a spring rod that fits into holes already in the minivan. I just removed the oval covers and found readymade curtain rod holders. Rear curtains are attached to sticky velcro (that doesn't stick all that well!).
Camco 45167 Reflective Door Window Cover Solar Door Shade Camper Trailer RV Shade reduces heat loss in the winter and reflects sunlight to keep out heat in the summer. Installs easily with Velcro tabs - included. 16"W x 24"L. 1 per pack. $8.49