I installed a couple of scissor jacks behind the fuel tank, making sure that when folded they did not touch the black water tank and when fully down the screws did not meet each other, buy the biggest ones that you can, some times you need the height when camping in National Parks.
I brought two pairs, installed two permanently and the other two I use up front when we are staying longer, I also carry a smaller scissor jack that I place close to the door to avoid rocking the RV when going in and out I carry them in the toad.
Do not weld the jacks to the frame, drill holes and use bolts if one jack gets bent it can be replaced easy.
navegator