Assuming you want to drive it while you bring it back from the edge:
1. Make it WHOA... Brakes - replace wheel cylinders, inspect brake lines, new shoes/pads, master cylinder.
2. Make it GO...Replace that engine, inspect the trans (assuming you have an auto) by dropping the pad. If there is an excess of "clutch mud" in the pad it may need a rebuild. If not, replace the front/rear seals, modulator, filter, pan gasket and button it back up. New u-joints (cheap insurance), drain the differential, pull the cover, any metal here is no good, if no metal replace the gasket and cover, refill with gear lube. Check the radiator- leaking - replace, if not flush and refill.
3. Make it SHOW...Replace the rusty panels. It is not that hard and they are not too expensive for your truck if you do the work yourself. If you do not have a welder you can rent one from Home Depot. Hold off on the extraneous panels like the cowl hood or roll pan until a later time unless you have the extra $$. Do the body work yourself and save $$$. Then you can take it to the local Maaco and get a decent paint job or do it yourself also.
You can install you seats anytime but make all the important systems work well first. Anyone who know these truck will appreciate your efforts and give you a thumbs up when they see it. Thats my $0.02
