69 valiant first project

When I bought my '70 Duster, the body looked good, but the underpinnings were neglected. In my case, I did start from the rear and worked to the front. Rear brakes were ruined & useless by fluid contamination from rear axle fluid. As mentioned, get the important things done first, like brake inspection, steering, and the like. Build the car the way you want as you are replacing parts. My rear springs were bad, so I opted to get better ones with a little more lift. Lots of folks go for the appearance of a car with little attention to the important things. Have fun, sounds like a great project!
ah, I too was drawn into the "hey! body is straight!"
For my car, everything was neglected and all of the brakes except one had broken springs, bad wheel cylinders, Shoes with no shoe just metal, etc. All of the wiring was a mess, (as in looped wire ends as connecters), the distributor did not. Then, the gas tank had no gas cap on it for 40+ years and well, I just ordered a new one as the one that it had is not worth fixing. All upholstery was gone, under dash wiring was bare and broken wires everywhere, brake light sockets that were connected by twisting the wires together. All of the locks are broken, dents? yup. ball joints? maybe. rust? definitely.
After finding papers and stuff in the car, i figured out why the car was in a vegas impound yard.
The car was originally from colorado, and the family that had it most likely did not have the money to fix it when it broke hence the ruined everything and poorly fixed all of it. The scenario probably was that the family went on a vacation to vegas, a cop pulled them over, and said that the car was unfit to be on the road and impounded it. (since the brakes had to have been screeeching like a banshee.) And in the impound yard is where it sat until I bought it.
There are just things like that you need to think about. the what why and how of the repairs on the car and how hard of a life it led just to get a rough idea of what you should fix first.