I use ladder rests made from plywood and foam rubber. 1/4 plywood is flexible enough that is can be screwed to contoured plywood supports. A rest is attached to one section of extension ladder with wire ties and another section with a rest is placed on the opposite side of the AS. The ladder bottoms are may be tied with a rope under the trailer. Scaffolding can be placed between the ladder upper rungs.
To copy the AS contour, I used a wire (coat hanger) and bent it to match the contour. This was transferred to cardboard to make a template and then transferred to wood stock.
After the wood assembly with screws and glue, foam rubber was glued in place. Holes are drilled at spacings to accommodate the wire ties and ladder rung spacing.
AS mechanics have told me it is OK to walk on the roof. But you have to get up there somehow and I am not agile enough to walk on the roof, confident that I won’t do damage. Besides, I believe in Murphy’s Law.