I have the Sundance 310QB. It has a door that slides for the front bedroom and one that slides for the bunkhouse. It's on a track and you just slide it back and forth. The problem I have is the one for the front bedroom will not stay on track while in transit to the campgrounds. It has the strap that snaps to the door and the wall to keep it in place, but one of the two little roller deals that is connected to the track keeps co ming off and the door is laying over when I get to where I am going. I'm afraid it is going to hit the wall or damage the floor from the bottom corner hitting it. Does anyone know how to remedy this problem? I've tried adjusting the deal where it is hooked to the track, but hasn't made a difference. Does anyone else have this problem. The door in the bunkhouse is same set up and never moves.