My son and I are about to embark on this project. We'll keep a record of the restoration. I'll post pics from time to time. And PLEASE feel free to offer any advice.
This is a great project for you and your son to do! Good for you! Do post pix and ask questions as you go along. Don't get in a hurry as this will take some time (more than most anticipate); just keep steadily after it. And . . . whatever you think that this restoration is going to cost; if you double it you will be closer to the truth.
Others will give good advice about how to proceed and in what order. My advice is to keep an accurate record of everything that you do. In my opinion, this will make the project more interesting.
Take before and after pictures of everything that you do. You cannot take too many! You will take a series of pix of some thing or some area. Later on you will try to remember how something went together or was wired or what finish was it, and now you can go back and find out. When I started in this hobby I had to consider how much it would cost me for the ASA 400 35 mm film for my camera and then how much to develop each pix. Just be glad you don't have to worry about that now. File each series of pix in a folder on your computer by date and area of work.
Buy a 100 page 8-1/2 x 11 spiral notebook. Record a history of everything that you do on the car. Start with a section that documents all of the data of the car. E.g., VIN, body number plate, engine number, transmission code, rear end code; and then what each of those mean. If you don't have the references to decode those -- guess what? Team Chevelle can tell you! In the notebook, write down everything that you do and then list what needs to be done or what parts need to be ordered. Note the dates there the date that you took pix of that area to make it easier to go back and review what you did and how it needs to go back together.
Optional: Have separate sections in your notebook where you track, by date, how many hours you spend on this project and how much $ you spend. I have done this and found that my pre-restoration estimates were way low. Warning: if asked by significant others how many hours or dollars have been invested on this project, you can't say "oh a lot - I just don't know."
Good luck with your '68.