[dsraven]

also suggest to keep the trans member in place till the new part is installed, tghen use some sort of support there so the front cab mounts will still have integrity. otherwise door gaps and fender fitment can be affected from frame flex causing the cab to move a bit.
just my thoughts.
body looks to be in great shape, is that how you got it?
rewire is a great idea, then you know what you have.