The roof probably has a very thin layer of plywood or particle board. Sometimes there are weak spots due to poor quality wood. There may be trusses widely spaced. Sometimes an extra truss is installed where something heavy is mounted on the roof like an air conditioner.
Wear soft sole, clean shoes. Step with extreme care. Feel for support underneath before putting weight on the spot. Try to step where truss is.
I have an ultra light Kodiak Cub. I use a 4X4 piece of 1/2 inch ply to step on when ever I can. I don't put my weight on the roof unless absolutely necessary.
Please feel free to start your own thread for new questions.
I wish you good luck and happy trails ahead!
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