Well, as you know mine was basically a total loss before I got it... so my first order of business was to take it all apart and figure out what was salvageable. Mine was also a much more common car than yours ('71 H-Codes are WAY more plentiful than '72 Q-Codes, after all). I just wanted a cool '71 Mach 1 that would be mine, as-in: the way I wanted it. So the question of whether to restomod, customize, et al, was pretty much already answered before I started out.
I started out removing the front end components because I knew the engine was coming out. Once everything was out/off, I could refurb the engine compartment, firewall, etc., but since the front frame was toast, I would have to replace the whole front clip - so my focus changed slightly. After that, I made my way toward the back, floors, then the cowl, then the trunk and rearward sheet metal. As I got a new section done, I'd put the corresponding things back on (front clip followed by front suspension/steering, trunk area followed by rear suspension, etc.). Somewhere in there, I got the brakes and driveline reinstalled and fired up the car once the rear sheet metal was done and I hung the gas tank and plumbed the fuel system. When I finally had all of the damaged sheet metal replaced, it was basically time for paint & body, and after that, exterior details and interior, followed by the glass (it's helpful to not have the windshield in-place with rewiring the dashboard). The last things that went on the night before the first car show I took it to were the Mach 1 decals... at 11:30PM. Since then, it's been little things (LED light bulbs in the dash, RCCI Tach Conversion, ammeter-to-voltmeter conversion, etc.).
I found it was better to break things down into sub-projects, and complete each sub-project before moving on to the next one as much as possible (unless you were waiting on parts, or the machine shop, or something else - then move onto something else, and come back once the delay has been resolved).
Take breaks. Don't dive in, go balls to the wall in an attempt to get this done within some ridiculously-set goal or timeline - you'll just burn yourself out in a short amount of time. Murphy will be watching, after all - any opportunity to slow down progress will present itself. Don't get frustrated if something doesn't happen as quickly as you want it to - stuff happens and priorities change. Do what you can, when you can... and when you can't, come back to it when you can.
Be flexible and roll with the changes as they come. Don't sacrifice your real life for this - at the end of the day it's just a car, after all. If you have a list, and discover something you forgot to add to the list, make some space and add it to the list, and go from there.
If you get tired of working on one thing, make note of your progress and stopping point, then go work on something else. Sometimes, stepping away from something that's wearing you out, can give you a fresh perspective when you get back to it (but only if you can pick up where you left off, instead of having to start from scratch and do it over).
Along the way, take lots of pics, and catalog the parts you plan on re-using, store them in a secure/safe place you can find later, and add the parts you can't reuse to that spreadsheet I gave you (then go 'shopping'). Having the parts off and out of the way will make things easier to repair/replace, as well as help eliminate some of the confusion when it's time to all go back together. I relied on memory for a lot of that, and now I have several boxes of parts and various things taking up space in my garage that I can't just toss out because the old parts are intermingled with some new stuff. There never seems to be time to just go through and toss out the old stuff, either. The biggest reason for that, is because of the invaluable advice Dan (72HCode) offers up to everybody: never throw anything away until you are done. If you toss out anything before you've replaced every aspect of it, you might regret losing some unobtainium-based pieces, and risk having to purchase expensive replacements that may or may not fit back on. For instance, dashboard switches and bezels - no matter how bad they might be, do not throw any of them away. If you can re-use or refurbish them, you're good. If they look beat-up, missing the plastic chrome, etc., keep in mind they don't reproduce them. So, in order to get nicer ones, you'll have to find some nicer used units and likely pay through the nose for them. Better to just repaint them with silver paint (if nothing else) and put them back on until you find a better set or way to make them chrome again.
Don't be afraid to ask questions. There are no stupid questions... OK, so maybe there actually are. But, unless you're asking how to make your Honda Civic outrun a Boss 429, you won't be asking a stupid question. rofl No matter what you're up against, someone here has done it, been through it, conquered it, or are working on it. You're not alone in this. One of the biggest things this site did for me was encourage me and offer up the right advice when I needed it... and for that, I will ever be grateful, in addition I will be one of the biggest cheerleaders around (at 6'5" that's not an entirely untrue statement - LOL) since I am fortunately now at the point in my project where I actually have some experience to share, advice to give, and results to show. I also have some examples of 'what not to do' that I'm happy to share in order to spare the grief of repeating my mistakes.
I hope this helps. I know it's a lot to take in, but this is totally doable. You got this. ::thumb::