Simple test
Park in the shade?
Turn on the heat in the camper
Allow camper to warm up
Place bare hand on outside roof
Is roof warm to touch?
Yes you can try it,
No.. for get it!
Leave heat on in camper until roof fully cures
Could be several days
Heat/ambient temp is a BIG factor , the No Mix type rubber coat, cures by exposure to Dry Air
If the air is too cool and damp, it will take on moisture every night, it could take weeks to cure, provided it doesn't rain or snow during those weeks
One that might cure better in this environment, is the real liquid roof, the one that is a two part mix with catolyst , it cures via chemical reaction, once mixed it must be used, any unused portion left in the pail will eventually cure solid, it can be stored for a few days in the fridge to allow second coat, touch up etc..
