I am actually doing a gut/restore. Had to remove/replace rotted floor, so I actually have some experience. I have had the door frame off to replace the wooden inside frame that the aluminum outside frame screws to previously. My guess is that the whole door including frame could be removed by taking the perimeter screws out. even if locked. In fact you do want the door closed to remove the frame to maintain structure.
In this instance, I had actually taken one of the inside window frames off the day prior to getting locked out
to replace the wood panelling on that side of the camper. So I was then able to pop the window off from the outside, and crawl through the window.
My ultimate problem was not the locking mechanism, but the door striker which was bent. I replaced it (8 bucks at a local rv shop). I should have done it a long time ago. Life is good again!