My truck did not have any power accessories with the exception of the back window.  I have a lot of experience working with Toyotas as I have had my 87 Supra Turbo for so long and new that transplanting these from a donor vehicle wouldn't be too hard.  It turned out to be harder than I thought.

With the door panels off, I saw that the doors had extra bolt holes, I assumed they were for the power regulators.  However, I also noticed that there wasn't any wires running from the body to the door.  Uh-oh, my experience says cars usually have all the plugs and wires in place and one just has to add the modules. 

I started by getting a Toyota Electrical Manual for my truck and using it to get a rough idea of where all the connectors and relays would be.  I then started searching junkyards.  I found one with wrecked doors and started taking things apart to follow the wiring around.  I then went to my truck and made comparisons.  I had none of the parts needed- no connectors, wiring, regulators, or control modules.  This meant building a completely parallel wiring harness.  I took everything I needed from the donor truck by just cutting the connectors off with a few inches of wire hanging from the end.  I ended up with the arm rest and switch modules from all four doors, the window switch module connector and mirror switch module connector and mirror connector from the driver' door, the 3 male and 3 female connectors from the driver's kick panel, the door control module and its connector from under the driver's side of the dash, the 2 male and 2 female connectors from the passenger's kick panel, the window switch module connector and mirror connector from the passenger's door, the male and female connectors from the rear driver's side kick panel and the male and female connectors from the rear passenger's kick panel, the switch module connector from the rear driver's door, and the switch module connector from the rear passenger's door.

I had to drill the holes in the frames and that required that the doors be taken completely off the truck.  There are obvious flat places where the holes should be.  With doors re-hung, I installed the rubber wire runner that spans the door jamb. 

I've done quite a bit of electrical wiring, and soldering over my years in the Navy and knew that I could build the needed harness.  With the Toyota wiring manual, I listed each wire per line using columns to show starting pin, the color, gauge, signal, and destination(s).  Example: IF1-pin9  light blue with white stripe  12gauge  door lock  II2-5, BO1-6, PP1-6, BK2-7, and GM1-8.  When I go to another connector where I had already listed the wire, I just referenced back to it.  Example: II2-5  light blue with white stripe  12 gauge  door lock  see IF1-9.  There were a couple of mistakes in my manual as I figured the actual wire colors I had in my hands were more accurate than the printing in the manual.  With this written map, I ran the new wire around the truck to get a rough length, cutting each one about where the connectors would be and being sure to cut long.  A lot of soldering, cleaning, and heat shrinking later, the wiring harness was done.  I then wrapped it all in electrical tape and ran it through the factory looms.  The mount for the door control relay was in my truck.

To replace the regulators, I removed the two bolts that hold the window.  I then ran 2 loops of tape from the inside of the window over the frame to the outside of the window to hold it up.  Swapping of the regulators was easy as the extra holes in the doors were for the power regulators.

Unfortunately, the new arm rests do not cover the holes where the old hand cranks came through.  I will be building new door panels for a stereo anyway, so this was no big deal to me.  With everything in place and hooked up it was time to try the stuff out.  Yeah, it all works.  I do not have power mirrors yet, as I do not have the mirrors themselves, but all the wiring and switches are in place.

1- With practically nothing in place for power accessories, this mod becomes very extensive and requires a good working knowledge of wiring.

2- All the junk yards in my area are way too proud of their stuff and will not allow parts to be taken off of doors and such if they can sell the door whole.  I had to keep making trips back to them until I found a 4Runner that had wrecked doors (that's why no mirrors).

3- The arm rests I got were tan and I had to paint them grey to match my interior.

1- No real problems other than the hole for the door crank be exposed.  I could have got he door panels too, I guess if I had found one that had the same color interior 

This payoff was purely personal.  I like having the power windows- I couldn't roll all the windows down by hand while rolling down the road for example.  The biggest reason I did this was to allow the install of an alarm that could lock doors when it armed.