I would go ahead and buy most everything you can now and have it shipped with the car. Frame rails, full floor, inner-outer quarters, trim, hood, wiring harnesses, etc... everything!
If you don't need the new, or the old is ok you can probably sell either since you'll have the only one locally available. An entire Goodmark-NPD-Ames order wouldn't be that bad in the grand scheme of things. 10 grand or so of parts up front will same you a lot of headache down the line.
Better to have it and not need it than need it and not have it.
Wanting a Custom fit in an off the rack world.
I don't have time for a job, I just need the money.