I was considering buying a pop up camper at one point. I also thought about ways to bring a bike along with me. Putting them on the roof just isn't an option for me. Most everyone else covered the reasons, and my gut feeling tells me "DON'T DO IT". ;) The one thought I did entertain was to find a pop up trailer that had the front storage compartment (cargo area separate from the box). I thought of removing the storage compartment, using the extra space on the frame, and possibly mounting a rail sideways on the frame to hold the bike. As for roof-mounting, mounting to the back bumper, extended reciever hitch, I see big flashing yellow lights telling me it would be a big safety hazzard or more.