I DK about your composite surface material or its lamination tensile strength, but I can tell you I’ve had rock solid adhesion of 8020 to my aluminum camper skin for 16 months using 3M VHB tape (5259 Edit: 5952 - I seem to always get that backwards)) and thats through two Phoenix summers so far. I actually wanted to remove some but its permanent. They build airplanes with the stuff, so …
You can also attach to non metalic surfaces well, but may need to use 3M’s VHB primer. 3M also makes an LSE tape for low surface energy materials (think vinyl or rubber) that works very well too. If you’re real concerned about loads, and your composite can take some screws that will make small sections completely rigid. I don’t think bigger sections (12” or more) need any mechanical fasteners.
If, for instance, you have a cabinet supported by the floor and then adhered to the camper wall along the top edges, its not gonna move *as long as* you do your surface prep correctly. I’d also suggest using smooth sided 8020 for the side VHB’d to the wall to increase the square inches in contact with the tape.