My Thor has the batteries under the steps too. I have to remove them from the back side by tipping them a little and sliding them between the frame rails. I lift and tip it from the front side and I have a helper under the RV that I pass them to. After labeling and disconnecting the cables, negative first, I tape a piece of rubber over the positive terminal to insure it won't ground out then as suggested I wrap the top with a plastic bag in case some acid leaks while I'm moving the battery through that frame steel. A real pain...
