I'll follow that advice. I'll go with the panel adhesive because I don't have storage space for a welder. (I can rent a flux-core welder, but I understand they tend to burn through sheet metal.)
Here's the plan:
wash car
tape/paper off areas around the repair
grind to bare metal to expose all rust spots
spray with epoxy primer
cut out a rust spot
cut and bend a patch
cut and bend overlap pieces to go behind joint
(may need to use self-tapping screws where clamps won't go)
glue overlap pieces, let cure
glue patch to overlap pieces
(repeat cutting/gluing for each hole)
skim with fiber-filled body filler
blend with conventional body filler
spray with epoxy primer
sand 80 grit
alternately prime and sand with 220, 400, 600
paint: single-stage or base/clear? color is PPG 2136, Chrysler E5