We currently tow a 31' (I just measured it) 5th wheel with an extended pin box. I can "almost" make a full lock 3.5 lane U-turn with it without tapping the back of the cab of our short bed F250 and th...
You may want to consider a ProPride or Hensley Arrow hitch. The design of these hitches makes them longer than the std WD hitch, increasing the clearance between the truck and trailer. I can open the barn doors on the Suburban when hitched up, and also turn pretty sharp with the TT connected.
Side benefit, you will get the same towing stability and sway-free towing that you get with the 5er.