I installed a PopUp GN hitch in my MegaCab a week after I bought my truck. I pull a 30' GN flatbed and a 32' GN horse trailer with LQ on a regular basis. I have had NO problems whatsoever with cab interference. I added an offset to both of those trailers just in case, but frankly, I really did not need them. Yes, you ARE closer to the cab, but all you really need to do is pay attention. I have seen guys with long beds get into their cabs because they are not paying attention. The offsets are nice, they move the trailer back some away from the rear of the bed, leave you a little more room when you have the tailgate down and need to access the bed for something.
CD