Something to consider about the windshield rust. If the truck uses a rubber gasket making a leak free repair is more difficult than a glued in WS as you must maintain contours and a lip for the gasket to lock on to.

All rust will be 2 to 3 X visible size once you poke around and possibly 4 to 5 X once you get to good metal. When repairing rust by welding in metal, the back must be painted / rust proofed otherwise it will come through again.