Rockwood Mini Lite, exterior walls are likely 1" foam behind 1/8" or maybe even 1/16" luan. Interior walls will be about 1" empty space behind luan.
Through luan into the foam, I've had moderate success with light loads using plastic expansion screw anchors. You have to use a short (3/4" or less) screw and shorten the anchor to match. I drill only through the luan, drive the anchor into the foam. You do not want to drill far, won't take but a couple seconds to make it through to the outside of the RV.
Manufacturers embed anchor plates, heavier plywood or metal, into these laminated walls where ever they want to mount something. What you want to mount, you are on your own.
Hollow walls, if it is too heavy for a stick-on (i.e. will pull off the wall paper) it is probably too heavy for an anchor. Without the foam to dig into, the anchor doesn't help much, and 1/8" of luan won't hold much by itself.
Like some of the other posters, I like Command Strip, but they will be limited to the strength of what they are fastened to, and in a RV the weak point might be the wallpaper or fake wood plastic covering.