Moot point, gonzo - this car is not getting sold in the short or long-term. My primary interest is making sure it’s alive and kicking so I can teach MY kids to drive it.
It’s a baseline model (straight 6, AM radio, no A/C) but I love her just the same. Her name’s Jazzabel, btw.
There weren’t all that many options for MGBs. You could get a convertible top, a built-it-yourself top (stows in the ‘boot’), or a removable hardtop; a heater; a radio; and overdrive. I’ve got the BIY top and the other options. (I really like the overdrive.) While prices are rising, with chrome-bumper models being more desirable than later models, I have no intention of selling it. So while it cost more than anticipated, I agree that it’s a moot point.
I really like ‘mundane’ examples of things. It’s the idea that the things, in this case cars, represent an era; and the most mundane example is probably the most representative of the era. Or something. So there’s nothing wrong with a restored '64 Biscayne with a straight-six. To me it’s more representative of its time. OTOH, my dad had a '66 Ford Galaxie 500 7-Litre back then, and they’re less common than other Galaxie 500s. I’d like to have one of those. But only because dad had one. If I wanted a Galaxie 500 and dad didn’t have the 7-Litre model, then I’d go for one of the others.
I guess it’s just the idea that your average family would have an average car. Relatively few people had an Impala, say, with huge tires and and lowered suspension. Most Mustangs were sporty little cars that people just drove, not careering around corners pretending they’re Frank Bullitt. There’s something appealing about that.
My MG is a unibody. That means that repairing the structure and repairing the body cosmetically are the same thing; or at least that they go together. Your Biscayne is body-on-frame, which means that you can do the structure and save the cosmetics for later. The first thing you should do is make a list. IMO the first thing you want is brakes. As you can tell from my adventure, I would make them like they were when they came from the factory. But then, I’d probably take it down to the bare frame and have the frame powdercoated. 
What you’ll want to do is make sure they function perfectly. You might powdercoat the drums and make them look pretty, but really you want to inspect all of the lines, the master cylinder, the drums, pads, etc. and make them work like new; not necessarily look like new. And get new tires. It doesn’t matter if the tires you have look new; they can deteriorate. Get new ones.
IRAN (Inspect and Repair As Necessary) the suspension. People don’t pay enough attention to the suspension, and it really is a vital part of safety. It works in concert with the brakes, for example. Make sure the steering is perfect.
Overhaul the transmission. You don’t want a ‘wonky gearshift’. Replace the U-joints at the same time, and make sure the differential is fine.
If the engine is running well, I guess the next thing I’d look at is the electrical system. The coverings on wires can get brittle. Replacing the wiring harness(es) is a bit of a job, but then you won’t have to worry about it. But in any case make sure everything works.
Check the engine and cooling system. Fix any leaks. For the time being, as long as the engine is running well you don’t have to improve it. One thing about engine bays is that they get dirty. Make sure it’s clean. If your engine and engine bay are clean it will be easier to spot leaks later.
Think about the glass. It’s amazing how pitted and scratched they can become. In my case the good news is that windshields are still being made. The bad new is that my regular parts house only had ones that didn’t fit. (Fortunately Victoria British in Kansas had ones that did.) I don’t know the availability of glass for 40-year-old Chevys, so you may have to search a bit.
If I were you I’d try to get as original an upholstery kit as I could. It won’t matter if you just want to drive the car, but it will if you decide to do a proper restoration later on. Besides, original interiors look cool. Don’t forget to replace the rubber seals around the body and glass.
I wouldn’t paint a car gold. It’s just not what I like. If you like it, more power to you. But if I were going for originality I’d stick with the gold. Personally I like white on mid-'60s Chevys.
I think for three kilobucks you can have a safe daily driver with good brakes, good rubber, and steering and engine. It won’t be enough for upholstery and paint too. But I think a body-on-frame car is easier to fix up as you go along than a unibody.
IMO a rolling restoration will not be as good as a frame-up restoration. On the other hand, it meets the needs for your stated goal. The problem with rolling restorations is that if you want to make a showpiece, you’ll be restoring it twice, re-doing things you’ve already done.
You really should post some photos. 