Swapping to an auto you would need,
-4r100 or E4OD
-Superduty transfer case mounted to that (for an auto, since the input shafts are a different spline count)
-PCS with the proper harness
-Adapter plate from engine to trans, and the proper alignment dowels
-Crank spacer thingy (goes between flexplate and crank)
-Flexplate
-A shifter of some sort
-Trans. cooler
-Trans. cooler lines
I may be forgetting a thing or two but those are most of the things needed.
When I swapped from a ZF6 to a BTS I spent roughly $4k. Granted I got a pretty good deal on a used BTS, and shopped around for the rest of the parts. It took a little while to get everything together, but the only thing I didn't have when I went to install everything was that spacer between the crank and flexplate. The whole swap took about a day and was just about entirely a bolt in swap. I kept the manual PCM and steering column, put my shifter on the dash, and simply covered the hole in the floor with a plate and carpet.
The PCS is nothing short of awsome and would recommend using it to anyone. Lastly I am much happier with the auto, that I have complete control over vs. a ZF6 with any clutch that will hold decent power.