fix or part out

Decided to tackle some rust issues on the Dart today, got out the old sander and went to town. One thing led to another, and I'm pulling the trim off the back glass and pulling up part of the vinyl roof. funny how things can get out of hand. But, was sanding and sanding, and noticed that this one spot on the pillar wasn't showing bare metal like it should. so more sanding, and then i realized that someone had previously, and poorly, replaced the roof on the dart (or so I'm assuming from the looks of it, haven't worked on the other side yet) but here's my dilemma. I love the car, but I'd rather not drive a death trap and not sure if it's worth restoring now with the roof being what it is. ...I think the car's been in a wreck long ago so not sure what other secrets lie about.
what's good on the car:
glass except for the driver windshield, interior is in good shape minus the carpet, bumpers were rechromed 2 years ago, new holley 570 carb, trans shifts good, new engine wiring harness, the trunk has not rust or holes, rims
what's bad: the roof is bad, there's a dent in the passenger side quarter panel, there is some rust in the lower quarter panels, the rest of the electrical system should probably be replaced, the speedometer works but is off by 10 mphs when you're doing 60

so i put some pictures up, any opinion would be great