our king bed in our 1007 will tweak the rails really bad. did not know why it was so difficult to pull out and push in all the time. on inspecting the rails they had actually gotten deformed from the king hanging out there until the bed supports were installed. what we do now is pull it out and with the wife supporting the end ever so slightly , I install the supports. that takes the pressure off the rails and helps them not to get tweaked. so maybe look at your rails and see if they are deformed at all. ours slides significantly better now. lubrication from time to time also helps on the rails and the roof supports. we do need to lift up a bit so it doesn't catch on the weatherstrip on the camper body. hope that helps.
2000 dodge ram laramie slt,cummins, 2014 jayco eagle touring edition 28.5 rkds, 1996 scamper 065s