Trying to finally get my first Muscle Car - I’m nervous

You've been given some great advice so far.
A little more advice, if I may...
If you don't intend to at least attempt to learn to tinker with this thing, go buy a new or lightly used Chally. You will be much happier in the end and it will serve your purposes.
Older A bodies take TLC and if you try to pay someone to do it for you, your A will eat you alive. That is, provided you find someone who doesn't totally butch your ride. These cars are going on 50 years old now, some already are. If you want one, great. But expect that you will be the student and your car will be the teacher for a good while. The folks on this forum are the best there is when it comes to helping and mentoring. But if all you intend to do is drive it (and break it) this is not the hobby for you.
That being said...it ain't rocket science. Don't be afraid of it. Cars "back in the day" were nowhere near as complex nor computer controlled. If your heart is set on a Demon, take some of the advice given and build one out of a Duster or Dart. FWIW, ain't a thing wrong with either one of them. If you expect to find an H-code car, expect to pay for it. Much easier to build your own replica from a 318 car and not have to worry about devaluing it or screwing something up. A whole lot cheaper, too. Just my two cents.

EDIT: Also, working on your project car in the parking lot of ANYWHERE is a really, really BAD idea. Find someone local willing to rent out garage space. Dusters, Demons and Darts are famous for rusting out. Even parking one outside is asking for Big Trouble.