Originally Posted by kraftengr
<<snip>> Our unit came with hooks mounted in the ceiling for a canvas pantry, and I've seen clothing racks that can be purchased and mounted in pop ups as well. <<snip>> In short - work smart and don't overload!
Ditto on this great answer. If you want cup hooks, there are numerous places to attach them without screwing into the roof. The hanging pantries attach to loops fixed to the ceiling with thru bolts - the bolts are installed before the roof layer is applied to the plywood. You could create a cup holder that hangs from a pair of these, or you could add a board with cup hooks to the bottom of a folding pantry. There are also curtain rails in many locations and many have a wardrobe bar as well. If you drill a horizontal hole in the privacy curtain rail separating the bathroom from the living room and use "S" hooks, you could create cup holders without penetrating the roof, where one slip with the drill could ruin your day.
The roof sandwich may be vinyl/plywood/plastic, so a screw would hold better there than in the particle board walls, but the plywood is thin. I also suspect the plywood is "sheathing" grade - not "furniture" grade. So you could easily hit voids in the ply and have little to hold the screw. If you put a screw into the plywood, I'd strongly recommend using something like gorilla glue to make it hold better. Drill a tiny hole, use a toothpick to put glue into the hole and put some on the threads. Install the screw while the glue is wet. If you haven't used Gorilla glue, don't overdo it, because it's messy and expands...and it's very hard to clean it off.
One other option
: You can through-bolt pretty much anything to the roof sidewall under the bag awning. The awning will protect it from leaking (and you can add a drop of caulk too), and the through bolts will give you the kind of strength to hold a heavy load...even pots and pans. I repaired the angle bracket that holds the bottom of my door for transport with through bolts. The screws stripped out and the substrate (seemed like particle board) couldn't hold even a much larger screw--even with glue. 3/16" stainless bolts did the job. If you use this method, plan carefully. Whatever bracket you install may interfere with the glass stove top or sink faucet hardware. But with some ingenuity, you could permanently install a base bracket and then add other bracketry and hooks that will hold quite heavy items. I haven't investigated fit, but something like this could be mounted with through bolts. Just be sure to use some larger washers on the outside to reinforce against the load and round headed bolts that won't chafe the back-side of the bag awning : https://www.hayneedle.com/product/ca...allpotrack.cfm