I added a bunch of pictures to the Google drive folder. The rust at the corner of the furnace outlet is solid, I think the heat from the furnace exhaust has caused the paint to flake off there. The other two pictures are of the body rust behind the rear wheels. It isn't a structural area but doesn't look all that attractive if you get up close. It hasn't spread since I've had the van.
The pictures of the chassis show some of the areas that have been treated with POR-15, and some areas that haven't yet. About 80-90% is POR-15 covered. Every time I had work done (gas tank, springs, battery) I had them coat the blind areas covered up by those components. I painted most of the exposed areas when I did the bumpers/hitch and other stuff.
"A job worth doing is worth doing at least twice."