Quick look at some pictures of the 8-11 and it shows an protrusion out behind the wheel well on the passenger side. This alone makes it wider than 4' at that location and will prevent the use.
Not sure of any hard side TC that doesn't use the space above or behind the wheel well. Though not familiar with every model over the years.
The RamBox seems great for having extra lockable storage space with just the truck, but is of no use when using the truck camper on. Plus if you have it full of junk, that is less weight left over for the camper.
2015 Ram 3500 4x4 Crew Cab SRW 6.4 Hemi LB 3.73 (12.4 hand calc avg mpg after 92,000 miles with camper)
2004 Lance 815 (prev: 2004 FW 35'; 1994 TT 30'; Tents)