I just pulled an 8 foot pop up with my wife, 3 year old son and our 3 year old Boxer 400 miles round trip with our TJ. In fact we just unpacked and settled in. I think 10' would be doable, but I certainly would not want to go larger than that. In my 97 owners manual it has a picture depicting yes to pop ups no to any other kind of camper. I think it has to do with side to side sway with the wind. At highway speeds we were ok. 75 mph was groovy, 80 the darn thing was walking right and left. Needless to say we stayed at 5 over or 75 mph.