Installing TV in Toy Hauler

Duct tape it.

You should be able to press on the wallboard to locate the studs. There has to be one at each door frame and probably one on the middle. Attach a sheet of plywood to the studs then mount your TV mount to that.

phone or email Dutchmen and ask for a diagram of that wall section. I bought a Heartland Fuel 352 and called and they emailed me a factory sheet that shows dimensions and how the wall is built. Since yours is above where the "factory" location is for a TV, they should supply you with drawings showing the stud locations. For mine I cut a piece of 1-1/4" thick board a little bigger than the TV wall mount. I mounted the board to the factory TV backing in the wall (which ws smaller than the TV wall mount). Then I mounted the TV wall mount to my mounted board.

Retired JSO wrote:
..I would then attack an outside backer board...

What did backer boards ever do to you?

Chances are that loft wall will have a few 2X2’s which should show up on a stud finder. I would then attack an outside backer board to 2 of the vertical supports then lag screw the TV mount to that backer board.

Behind that upper area is the loft which is accessible from living area.

I did the backer board deal on my old toy hauler. The original cabinet for the TV was for a CRT, so could not put a decent flat screen there plus didn't like the height. mounted bracket to board, screwed board to studs. Mine was a homemade rigid mount.

Am assuming the other side of this wall area is storage of some sort that is accessible from the inside of your rig? If so I would be inclined to mount a board on both sides and bolt/screw them together with a support board on the inside.

Check for studs and see if your mount would hit any studs. If not, yep- a backer board that DOES hit studs and then attach the TV mount to that.