How do i replace wiring in a 1970 jeep jeepster?

Do you want to replace all the wiring or just part? There's a company known as PAINLESS WIRING DO a google search on them, they are a leader in the wiring of autos, they can even make up a custom wiring harness if you need it. If you just need replacement wiring, maybe check the local salvage yards but that may be a tough find.