We did end up covering it, and i just saw last weekend that there was a small tear where it hits the corner of the camper. Hmmm. Think i will contact Adco - i hope i still have the receipt somewhere.
It was pretty easy to get on - DH up on the roof and some minor adjusting to get it straight. There were straps that went under to hold it in place, and then some ties in the front. There's a zipper, too, so we could get in there if we needed. I'm ready to take it off, tho, and get set up and organized - our first trip is in 2 weeks! Yay!
it's advisable to pad the sharp corner areas of the trailer before putting on a cover. some use foam noodles cut to fit.