Much of our old classics can be repaired with fairly basic tools like wrenches, sockets and screwdrivers. If you are mechanically inclined at all, you could get the manuals and do most of the work yourself. There are videos, books and lots of help on more than a few Mustang forums. Join a Mustang club and get to know the people who work on their cars.You would save lots of cash and have the satisfaction of doing it yourself, and probably doing it better than most shops. You could still pay to have those things done you don't feel comfortable doing. 10 grand at a shop doesn't go far on these beasts. It may seem daunting but many many people do their own suspension work. Its not rocket science. Look at your list- $475 for a clock? Come on, you could replace that, fix a rattle in the back seat, and adjust a window. I'll bet you could do almost all of that list, make friends and get lots of help here. Get your hands dirty!
If you must pay a shop for all these things then prioritize- above all else the car must be safe so do the brakes and steering first. The speedometer is fairly important but replacing the cable and perhaps the speedo is far less expensive than installing a Dakota Digital- although I must admit I lust after one myself.