There is no other way to properly clean and service componants up there, unless you get up there. I'm "large frame" as well, and was your weight for many years.... The roof seeems to hold me fine, but the factory ladders, and their roof attachment points are made for the 'little people".... I'd pad a decent ladder with an old blanket, and use that for access/egress.
2014 RAM 2500 Laramie 4x4 Quad Cab w/Cummins Turbo Diesel, 2009 Rockwood 2607, and 3 'yaks!
300W of Suntech Solar, a Rogue MPT-3024 Controller, and a Xantrex PW2000 Inverter