Yep, even in Dallas, you'll need to winterize unless you are parked indoors or have some other method of keeping it above 32. Like if it fits in your garage at home, you'd probably be ok just emptying the tanks... *probably* - I've seen some crazy ice storms out there. Hopefully the guy that owned it before you winterized too
but you'll find out soon.
Me personally, if the propane works, I probably wouldn't sweat it, but I'm sure some would say otherwise. I would give it a thorough inspection for cracking lines, 'hard rubber' etc.
As far as the roof goes, someone else will probably chime in. I'm not familiar with 'epoxy coatings' on campers. Most of us use Dicor products on our roofs.