Roof coatings - what to use?

We have a TT set up on a permanent site near the beach in Delaware. We have Oak tree coverage but a lot of sunlight. We just purchased the trailer on its site in September and we're doing some maintenance on it now. The roof of the trailer has a thin rubber like membrane. It is dry rotted in some spot and deteriorated away exposing the aluminum underneath. I have no desire to re-skin the roof. What is a good, thick product that I can roll or brush that will cover the membrane, cover the exposed areas and fill gaps? Also there is a screened in porch are with pre-fabbed panels. The seams between a few panels leak. From new it looks like some sort of sealer was rolled over the seam. What is a good product to use on this?

As for cleaning so adhesion is good are there any recommendations? Power washing is out because it will just tear through the roof membrane. Looking for something I can go up there with a brush and bucket and gently hose off. Let dry and apply coating.

Any tips would be greatly appreciated.

Thanks,