HUGE undertaking. Good luck with the project. I think you'll be surprised but you'll probably end up paying as much as just buying one. BUT, it will be new and a proudly hand-crafted machine.

I always felt the biggest issue with a scratch build like this is the wireforms. Those have a huge amount of nuance to them. But Adamms just has one and it's a fairly straight forward one. Plus, you have a friend nearby who I assume will let you borrow his to use as a template. The ramps and topper are vacuum formed plastic and generally available in the aftermarket. Subways and ball guides can be fabricated. Might be hard to source the thing hand and mechanism so start looking. Board sets won't be cheap especially if you want to stay original.

Good luck!
Jaz

Mmmmm..... puurrrrrrddddyyyyyy....