http://www.allstays.com/Campgrounds/
If you have an iPhone or iPad, this, in my opinion, is the best camping resource out there - it shows private campground, NFS, BLM, COE, Military (all including max rig length and lots of other information), steep grade, low clearance, propane dealers, Walmarts ("ask" and "not allowed"), Elk's, rest stops, turn outs - you name it, it's on there.
Plus, if there's too much information, and say your preference is COE parks, you can easily filter everything else but COEs out.
I just recently tried to help a friend with the online version and told her that the iPad app is much easier to use.
It's not 100% accurate, but dang, it's good.