we bolt those steps directly through the aluminum frame
make sure to drill your hold right in the middle of the frame (stronger that way)
we use a big washer, nut, and acorn nut (beauty cap) -- looks good
I can't ever remember a customer even noticing the bolts inside the camper here in the showroom (not very obvious)
When installing the rear wall steps after the fact, I think the guys here in the shop will take the camper trim off, peal the aluminum skin back a little on the rear wall to get an exact frame location, mark the skin and drill the holes.
Once the holes are drilled in the correct locations, it is a breeze to install the steps.
EXCEPTIONS: If you have a refrigerator or furnace in the camper, it is not always easy to put the rear wall steps on the driver's side. You might have to remove those in order to gain access for bolting the steps on. In that case, just put 2 steps on the passenger side and be done with it (not sure the steps would be worth the trouble of pulling the refrig or furnace just to have them) -- personal call I guess.
have a fun and safe holiday weekend !
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