John&Joey wrote:
If you ever carry an industrial rubber roof up a ladder I think you would have an appreciation for the difference in that rubber roof and a RV roof. 30-40 years I think is pretty optimistic. 20 years and beyond is a good number given the type of care it got. What you'll start noticing is a crazing that does not dry out as fast as your neighbors after a good dew. It's just a matter of time after that point.
To answer the OP I would be more concern with the plastics on the roof then anything. Since it was stored out of the sun you should be good, but UV's do destroy them after time. After a washing I would wipe them down with something like Protec-all or whatever you seem partial to. Skylights get brittle so you might want to see what the manufacturer suggest to use on it.
When I re roofed my FEMA trailer at my camp I used black 90 mil EPDM rubber it took two of us to get it up there. That dude was heavy.