The mounting screws for one bracket of my ladder also worked the fiberglass holes over size to where the original screws would not hold tight.
I cut a 1/4 inch thick piece of Aluminum about 1 inch larger than the diameter of the ladder mounting flange. Drilled a hole close to each of the 4 corners of the AL piece. Then applied a thin coat to one side of the AL backing piece with white caulking or RV Goop or ? (whatever I happened to have on hand, this would act as waterproofing and as a glue)
I could spring the ladder rails away from the RV just far enough so the wife could slide the AL between there and the RV without smearing the goop on the RV. When I released the ladder I drilled pilot holes in the RV, screwed the AL backing plate to the RV. Then I drilled, tapped and screwed the ladder mounting flange to the AL plate. That was about 10-12 years ago still holding tight! I did the other side to make it look even.