The only sites IMHO that are suited for a big unit is that one I mentioned right at the start of of the loop that do not involve driving into the loop:
MapI'm sure we stayed in either 111 or 113, the ones closer to the ranger station I think had horse trailers in them but I'm sure they did not have campers. The sites 520/22/24/26 might be possibilities but it seems their availability depends on the state of the river flooding.
We eventually moved to either 219 or 323 I'm not sure which but had a heck of a time getting in, we didn't damage anything getting out so we are not the ones referred to above but we did attract a crowd getting in. Getting to that site was no fun either dodging trees and boulders.
I don't recall what the odd numbers from 525 to 531 were like but you may want to look for photos. All of those 500 numbers would require driving against the traffic flow.
Arctic Fox 25Y Travel Trailer
2018 RAM 2500 6.7L 4WD shortbed
Straightline dual cam hitch
400W Solar with Victron controller
Superbumper