I'm doing something like this myself, mixing an '84 truck with an '86 EFI system and some other stuff.

The 89-95 efi system is the easiest to swap. All the wiring for the engine/efi are integrated into the engine harness and you can hook up everything at the chassis plugs inside the cab. The earlier system has the wiring for the coil/igniter and the MAF built in the chassis harness and you have to swap everything or make a sub-harness for those items. I'm swapping everything on my '84 body because I have all the stuff, I've also done the sub-harness thing on a 94 2wd body/86 4wd frame swap.

You need the tank with pump and the supply lines with the threaded fittings. Also need a return from the fuel rail to the tank

You also need the RE throttle cable.

The AC wiring should already be in the harness. It appears there's a section of ductwork in the heater system under the dash that can be replaced by the evaporator box, I can't verify because I don't have an AC equipped truck to look at - just pay close attention when you're stripping off the AC stuff and you should be able to figure out what you need pretty quickly

Can't help you with the shifter stuff, haven't been there yet