Big project but doable.
Myself, I would not attempt it without a donor vehicle.
Today I was looking on craigs list and saw a 1996 explorer 4x4 with a bad trans for $450.
I bought my 98 sport with a smooshed roof for $650.
I would look around your area for a donor vehicle that will fit your needs.
There are just so many items you will need, besides the obious mechanical like transfer case, transmission etc etc ... you will need the wiring and the switches, sensors.
You will need brackets and widgits and doo dads, you will wqant to look at the original for routing of wires, placement of new parts.
Really, I would not attempt this without a complete donor rig. And then I would be looking at fixing the donor using the 2 wheel drive for parts, it may be easier.
But for the main thing of all, have fun and enjoy the project
