I was at a national park last month, scoping out campsites on my bicycle, then asked about availability of sites. Some were for tents only. I specifically asked the ranger at the gate about parking a truck with TC at a tent only site. (He did not see my rig-I was on a bicycle!)
He produced a laminated card illustrating all kinds of vehicle configurations. From my memory, cars ok, cars with trailers, no. Regular SUVs and vans, ok, Class B looking vans, no. Trucks with shells, ok, Trucks with anything past the tailgate or over the cab, no. RVs, 5ers, trailers, no.
The only wiggle room I can think of might be an old, non-cabover Alaskan TC popup with the tailgate raised so it looks like a shell.
Just one mans observation at one campground at one NP.
FYI I believe there were no more sites of any kind available for the rest of the year. :E
