I use a single section of scaffolding alongside, a single expansion plank or 2x10 parallel to the trailer side and a chunk of 3/4" plywood approx. 24" x 48" bridging from the plank to the raised central section of the trolley roof. The vertical offset in the roof at each side acts as a beam or stiffener and the ply duckboard carries your wgt without transfer to the deflecting facets of the roof.
I rebedded my A/C, installed a FantasticFan, and replaced black and grey tank vent caps from this platform. I have pictures posted to an old thread on this site. Google some combo of Burro and air conditioner and you might come up with it. Or maybe Burro and Fantastc Fan install. I have lost weight
recently but when doing most of the above, I was 198.
You should not have to do repairs to central "fin." The mating flanges of the hull halves were bonded at manufacture and the seam is also bridged by glass layup on the interior. The TrimLoc cap atop the fin can come loose but should not effect water tightness of the underlying join.