I would get to the roof, ASAP. The caulk on the rear edge joint, roof to endwall, has lifted and is broken in parts. A couple of good rains may turn a $7000 trailer into a $700 unit, if water enters the wall cavity.
I think you must have done your homework about EPDM maintenance. Dicor and Eternabond are exactly what you should use to restore the areas on your roof. I would visit a roofing distributor and get enough white EPDM coating to recoat the roof.
The roof job could be done on a weekend day, easily if you have help. Make sure you clean everything well before applying sealants, tape, or coatings. When I did mine, I used detergent and followed up with Jasco Prepaint cleaner, a TSP substitute. It removes all of the oxidation on any surface. I spray it on with a garden tank sprayer. brush, and rinse. If you don't have a good water supply handy, I'd use the TSP substitute and wipe with wet rags. Any surface that you apply Eternabond tape to must be hospital-clean. Most guys use a solvent like alcohol, acetone, or what I had on hand, Lacquer thinner.
A few pics of my roof getting restored:
In progress with Eternabond being applied-
After coating-
Good luck with your roof!