We visited that area last year and it's gorgeous - but you already know that. We stayed at
Cannonville, UT KOA and also the
Wahweap Marina & Resort and for my money, the Wahweap was by far the nicer - it was more expensive, but nicer (sites more level, nice spaces between sites, full hookups. Even if you stay in Kanab, that's about the same amount of time away from the Coyote Buttes area.
As far as negotiating your way through with your trailer, you shouldn't have any problems. 89A coming out of Marble Canyon and to Kanab has some switchbacks, but if you're in Page, you shouldn't have to negotiate that with your trailer.
