So what's this going to cost?
Seriously though I agree with the outline above that Blazer laid out.
I spent over a year looking for a GM front 60 @ under $1K that was complete and not abused.
You got time so I would wait and watch for a 78/79 Ford front 60.
In the Phx area you will most likely go to $1,500 for a complete unit.
This brings into play just buying an entire rig.
I recently (last fall) missed out on an entire '79 F350 for a $800 (non-running) ranch truck in Silver City because I could not get over there fast enough and the ranch was in foreclosure.
As far as the t-case switch goes, just go aftermarket.
I have almost all of the parts needed for a 203/205 doubler setup that I have been piecing together for several years. I have way more $$ and time into it than I care to admit and it gets worse when you add up rebuilding the 208 twice in that time span.
I should have just bought an Atlas or something similar. At that point drop side does not matter, you can have them setup however you need them.