get a chalk line string from to back, pull it tight
check alignment, if the RV frame is square, then its the door that is sagging
a twisted chassis should also twist the window frame nearby
worn out door hinge and dragging door seem more likely to me, BUT? anything is possible
which corner did you jack up ? next to the door, or the other side of the RV ?
binding at the top or the bottom ?
do you need to use both doors, or is it just convenient to let the kids come and go thu the rear door
i know some RVs were built that way to allow easier bathroom access, or emg escape
