A 240Z for a first car would have been awesome.
One problem I see with that is... you are from WA. Where there is snow and they salt the road, cars rust. I think a 240Z would rust in outer space, so you might have some big issues there. You might get lucky, but check under the battery, the firewell, under the carpet where you sit (the floorboards), in the door jambs, around the taillights, and at the bottom of the hatch. I think
that's all the bad parts, evildky will correct me if I missed some.
If there is any rust there, get some rough sandpaper and get as much of it off as you can. Then get some automotive grey primer and spray it over any exposed metal. Anywhere you see a bubble or crack in the paint you should do this, it will slow the spread of rust. I wouldn't even worry about that broken stud until you get the rust under control if not completely fixed. Once you get a car on the road, it's much more difficult to make time for a big overhaul like putting in new floorboards. Plus, having Nissan put in a brand new engine costs less than having a good shop put in new steel everywhere you have rust (I've checked).
Now on any rust holes you find, you really should weld in new metal. If your father or a friend has welding skills, sand down the area, cut out the rusted section, cut a piece of fresh steel in the same shape, and weld in. Grind the weld down a bit, smooth with body filler, and prime. Now failing that, you can use fiberglass. They make this stuff called POR15, it should seal the steel a bit better than the off the shelf rattle can stuff. Same deal, get off as much rust as you can, coat the exposed steel and remaining rust with POR15. Fiberglass is pretty easy to use so I won't walk you through it, basically patch the hole, sand smooth, and prime. This isn't something I have ever recommended doing really, but given your inexperience with cars and taking a wild stab at your financial situation, I don't want to recommend cutting the floors out or anything like that.
Just use this to keep water out, heat out, or as something to rest your feet on.Remember that whatever you do with fiberglass is a temporary fix, as air can permeate fiberglass and the metal will find a way to rust. The floorboards in my 73 were repaired like this and the rust has since spread. So if you plan to keep the car for an extended period of time, expect to have to fix it the right way in... 10 years maybe.
Once the rust is dealt with, you can move to the running part. Does the motor run? If it hasn't been run in 8 years that's bad, but you can still try to start it if you would like. Drain all the old oil out of the motor, put in fresh stuff, then pour some into the cylinders through the spark plug holes. Let it sit overnight, and the oil should seep past the rings and lubricate everything so you don't screw up everything on startup. If it turns over well, then the motor is probably fine and you can start troubleshooting if you would like. I personally would pull the engine apart and replace the gaskets, piston rings, and bearings at a minimum. But pulling apart an engine isn't a beginner job so it might be something to hold off on for a while.
Once it idles, you will want to do a compression check. If any of the cylinders are out of spec for compression, you could try the oil overnight thing again and sometimes the rings will seal. If that doesn't work, you'll need to replace the rings. Which dictates replacing the gaskets. And removal of the pistons makes not replacing the bearings irresponsible. The block might also need machine work so let's hope that they all seal. If you need to tear it apart, start making friends who know how to dot this, who don't mind getting dirty. And then stock up on beer (of the root variety).
BTW: if the rings seal it isn't difficult to remove a broken stud from the head. It is easier with the head off though. If they don't seal, you can always have the shop that machines the block take care of it if you like.
Once you've got the engine rebuilt/running, you can start worrying about the rest of the mechanicals. First, the brakes. Check the reservoir, if it is empty you need to find the leak and fix it. If it isn't empty, you need to drain it and replace the fluid, then get your dad to help you bleed the brakes. Once all of that is taken care of, tell your dad you need to move it. Steer as he pushes, and slam on the brakes to make sure they work. If they work well, you might just get a laugh out of it. Now technically you could run on the pads and shoes you've got. But I would recommend replacing them (and for that matter, the rubber lines too) before you start driving it regularly.
Now check the clutch fluid, if there isn't any then you need to fix the leak. Otherwise swap it out and bleed the clutch. With that taken care of, it is technically driveable. The first two places you will want to drive it are a shop to change the tranny and diff fluids, and then likely the tire shop (200 miles, but how old are the tires?). At some point you will want to address the suspension which at the very least has worn out dampers, possibly springs, and I'd bet money that the bushings aren't in very good shape. My 73 has a lot of rust on the suspension pieces, nothing some time with a sand baster won't fix. It isn't really bad
in my 73, but it's certainly something to look out for as if it gets bad enough it can become a safety issue.
Now the car is driveable so you might want to make things pretty. Now here comes something completely out of the norm for me: take it to Maaco (or a similar shop). I usually advocate painting your own car, but I remember my first paint job (painted an FC... orange) and it turned out like crap. And that was in a garage with somebody who knew how to work the equipment. You get good quick when you have to keep buying paint, but for the cost of materials for the first try you can get a decent looking paint job done for you. Those places usually just suck at the prep work. I've seen a gorgeous paint job on a car done by a Maaco-like shop, but the factory pinstriping wasn't removed from one of the fenders.
But it turns out decent with good prep work, and will last as long as you take good care of it. So sand down the paint with 300, 500, 800 grit sandpapaer (in that order) everywhere there will be painted. Keep in mind that these places just spray over the outside, so some of the chrome trim might be best removed when it is sprayed. This also means that they won't paint the jambs/engine bay/under the hatch, so choose a matching color (you can pay extra for jambs, probably 50-75 per jamb/under the hatch, IDK what they would charge for the engine bay). Some of these places aren't so good at the masking, so look at some of the ones drying when you take it up to see how it turned out. If there's overspray on the windshield and such, you might want to mask it off yourself. After that; they spray it, you pick it up, you store it in a garage for 2 weeks as it cures, and then you buff and wax it. Most of these cheaper places use cheap one layer paint, so you need to keep it waxed and washed or it will fade out quick. A car cover wouldn't hurt either to keep the sun and rain (and snow you poor bastard) off of it if the garage isn't as easy to steal away from your father as it is mine.
The paint will further seal off the metal from rust, and now that it's all shiny you can turn to the interior. This is a great way to take advantage of the weeks in the garage when the paint is curing. Throw the dash cap in, then get to wiring! Hooking up the sound system isn't a difficult thing to do, you just need to know which wires to cut. If the car has the stock wiring for the head unit and speakers, I would recommend replacing them if you can, but no house wire please. Pull out as much of the interior as you can, you can run the wires and remove the old ones. It's not hard to do, it's basically just follow-the-wire-and-zip-tie. You father probably knows enough to show you how to wire up things. While the carpet and everything is out, look for rust. If you find any rust you missed before, say, near the spare tire... you know how to address that. A hand vac and some discretion on how you point the can is advised.
One that's done, throw the interior back in and start sourcing replacement parts for what's worn out. Congratulations, it's now been 1.5-2 years and you've brought a Z back from the edge of the grave.