Looking for advice. Want to build a Duster to run on a budget.

Doing what some consider " right " might be the wrong decision depending on what and how much they want to spend on a car. They can make the right choice for them .
I agree. Once again it’s better to do nothing then repair it wrong and cause more damage in the long run and have to redo it. Costing more. So if your argument is cost, then do nothing. It’s the cheapest. I’d rather have a rusty car then a rusty car covered in fiberglass and bondo with a paint job.