Be careful.....30yrs experience with Auto Extended "warranty" plans, more appropriately, service plans.
Stay away from any phone or mailed solicitations.
Not sure how a trailer plan would be amortized, without a lot of "mechanical", ie transmission, water pump etc., on a trailer just what would be covered is in question.
In the auto field, nothing in the cosmetic area; paint, upholstery, weatherstrip, (leaks) are covered.
Calling some AS dealers to see whats available would be a good place to start. Make sure to ask whats covered and what isn't.
Can't tell you the number of times I've heard...."but I bought a bumper to bumper warranty....everything should covered".......NOT!!