Honestly the rails don't inhibit our bed use at all. Don't know what rails you have, but ours are smooth and low profile (no bolt heads sticking up). We do carry some moving blankets to put down if we are moving large items. If hauling sand/gravel we will put a tarp down to aide in easy cleanup. I would think trying to 'level' your bed would be more of a pita than dealing with the rails. True, it can difficult to slide in long, heavy items, but we just jump in the bed and lift over rails.
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder