They do have a frame. I had an 04 Aruba, that I wanted to add another roof vent. I contacted Starcraft and they sent me drawings that showed where the roof framing was located, they didn't have drawings on electrical wiring. Apparently, their customer service has gone down a bit.
There are trim pieces on your ceiling. They hide the seams between ceiling panels, and, they line up with a framing member. The roof structure on my 04, had trusses, 16" on center.
Walls may be a different story.
Double check with a stud finder, before you make any cuts.
When I cut for a new roof vent, I used a zip saw, with blade depth set at the thickness of the paneling. I did find wires, but, only the ceiling panel was cut, and there was enough slack to move the wires out of the way.
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