Time to fix up Dad's old truck

[Jeepwm69]

Have an 1983 High Sierra, 305, 4 speed with low (SM465?), body is perfect (needs paint, but no rust/dents), probably about 60K miles on it.

Dad is getting older and about 18 months ago he threw a rock through the back windshield with the mower and the truck has been sitting since. I put a battery on it last weekend and it cranked, so it still runs, but it needs some work. Dad always used it as a work/ farm truck, but I'd like to get it really fixed up.

Problems to address

Starter is "clicking". The truck starts, but there was a clicking coming from starter area as if a low battery. I put a new Optima on there with full charge, so I'm going to clean/ reconnect the wires on the starter and see if that helps, and if not, I'll get a new starter for it.

Gas gauge reads full when ign is off, and when you turn key on it jumps to 3 oclock. From what I found here that means bad ground to sending unit or bad sending unit. That sound right?

AC does not hold charge. There is a streak of oil on the underside of the hood right over the compressor, so would this mean a compressor leak? I've retrofitted my Jeep CJ from R12 to R134, but I've got to find the leak here before I can do that to the truck. I've done some work here too on that and looks like I'll need to replace dryer/ oriface tube and adjust some other part (name escapes me at the moment). Looks like it has an R4 comprssor from the pics on autozones website. If the compressor is leaking, I figure I'd be better off just getting a new one unless these things are easy to fix.

Speedo quit working several years ago, and the mechanic took the little box off (it had seized up) and screwed the cable straight into the tranny. It reads about 10mph slow. Anyone know a parts house where I can get another box? I don't have the original and I'm sure it has a speedo gear similar to my CJ's so that might be a chore. Speedo also squeaks. Not sure if it's the cable or the gauge. Guess I'll unhook the cable and see if the squeaking stops and that will tell me which it is. If it's the speedo is there a way to lubricate it?

Doors sag. Can I just get new hinge pins and bushings for this?

Dash is cracked badly. Do the glue on dash covers look decent? I don't want to spend $300 on a new pad, but I don't want to spend $125 on something that won't look good either. Not looking for a show truck, but want it to look nice.

I want to fix the above things and get the outside painted/ trim reattached.

Dad lives 5 hours from me so it will be a little bit at a time, but I'm trying to get my info straight so I know where to go when I get back to the truck.