We have a class C and the wife was afraid the kid would fall out too. I put a wide flat board under the mattress that ran the length of the bed. I made rails similar to bunk bed rails and attached them to the board using L brackets. I used oak wood and finished it up nice to match the woodwork in the mh. They still look great. I didn't want to have to attach anything to the mh, so the board under the mattress holds it in place. Let me know if you want pictures. We took it in for service and they asked us where we had them made, as they looked factory made.