Back on topic....
Yes. I do have trouble making a plan and often have trouble sticking to one IF I made one.
Most of the project cars I get are non running and need body and paint. If it is going to be painted the same color, I often get the car running so it can be moved around easily. A running car is great for backing out of the shop to clean it in between block sanding sessions, to blow the body filler dust out of the shop, etc.

I really should develop a specific regimen for building cars.
Something like....
* Body and paint.
* Building all SUB-systems such as engine-trans-drive shaft-axle., Suspension, brake and steering, interior and stereo, etc.
* Final assembly.

It would be easier if I had all the needed parts when the project begins but so often, I need to go to swap meets, talk to friends or look online until stuff becomes available. Instead of sitting around, sometimes you have to do things out of order just to keep the project moving along.