Walking on an RV Roof
Underlying the rubber covering is usually a 3/16th to 1/2 inch plywood or particle board sheeting that evenly supports your weight. If your roof is metal, especially if it is the seamed type, (has crosswise seams every 48 inches or so), then lay a plywood strip or some wide boards (lengthwise) to walk on. This way the boards span the roof rafters and distribute your weight evenly on several supports. Be sure to check your shoes for imbedded pebbles or other sharp objects that may damage the roof material.
RV ROOF Sealant
Closely inspect the roof sealant condition on every fixture or seam. Any cracks or thin spots can be touched up with the appropriate material sealing material. If the roof sealant is peeling or flaking in any way, then the old coating must be removed by scraping it off. On metal roofs I use a 1' wide scraper with a firm blade, like the ones used by auto technicians for scraping off old gaskets. For rubber roofs I made a plastic scraper that won't cut the membrane. If you heat the old coating with a hot air gun, it will come off fairly easily. You should inspect the roof every Spring and a gain in the Fall to catch any potential problem with the sealant.