I also would clean up and see what lies beneath prior to doing full panels. Jim Carters sell patch panels that go up to the beltline. I redid the bottom of the doors on my truck but they weren't too bad. I measured and drew a straight line here and then cut with a cutoff wheel and nibbler. This is what it looked like after flanging the door and prior a quick sandblast. Here is after a prep called "Right Stuff" and this is what it looked like after it dried. I bent up a piece of sheet metal and flat folded the bottoms and ends . Holes were punched here and then welded in this shot. Here is a shot after the bondo. You should hang door before primer to check fit. I don't have any shots of the door in primer but this is a shot after paint. Maybe one of these shots will help you decide which route is best for you. Have fun and good luck.
Dan