06 short bed crew cab, Anderson 16k hitch, 31' Denali 5th wheel. Never had an issue without having the slider. There is literally only one spot I can ever remember trying to get into where I was "close" but the bigger issue was that my truck was so close if not past 90* that I wasn't moving the trailer in the direction I wanted anyways. My trailer does have the concaved front cap, which I *think* all newer trailers have, so you should be fine without a slider. But like many say, better to have and not need than need and not have. With that said, its nice to not have to load that extra weight of a slider in/out of the bed since during non-camping seasons I remove mine.
Bought 6/16/11: 2006 Chevy Silverado 2500HD, 6.6L Diesel (LBZ), CCSB, Bose system, leather. Southern Comfort Conversions edition. Includes: Custom faded two tone paint job, leveling kit, 18" chrome wheels, aftermarket interior trim, billet grille, remote start, wheel to wheel steps, and Line X installed. I upgraded to: Cognito UCA kit w/ shock extenders and Bilstien 5100's, Tie rod sleeves, 300W Rockford Fosgate Amp & 2 JL 8" subs behind rear seat, Tinted front windows to match, BakFlip F1 Tonneau cover, Reese 15k 5th wheel hitch, Prodigy brake controller, Toyo AT2's 295/55/R20 w/ Ultra 203 Hunter 20x9, -12, LED Concepts Colormorph Halo kit upper & lower.