the harness is roughly $500 or so. Crossmember say $300. Headers are tricky cause they are what they are and there aren't many out there. The accessories are the same as the GN motor minus the power steering pump which can be found in the bone yard(i believe sunbirds had the pump)
It all depends on what you want to do the swap. If a/c is a need then you'll pay for the parts. If not everything else can be accomplicshed using the GN components.
IMO the cheapest way to do it would be this:
Use the GN harness and splice it together(or laying out the cash for a TTA harness would be easier but more costly).
Grab a heater only box for the f body and use the GN engine, headers and crossover.
Mount the 700r4 to the engine with the adapter plate(just lay the engine on the k member with the mounts assembled, upper n lowers) put it in the crossmember bolt up the tourqe arm and driveshaft.
Now mark where the holes in the frame pads sit and redrill the k member and bolt it up.
That would be the cheapest way to do it using parts that are more available than trying to find TTA parts.
The only real cash layout I'd do is the harness messing with the loom and hacking one up is cheaper, but it's a p.i.t.a.
HTH!