It's time consuming, especially since it will be your first one. But not all that difficult.
Not sure what the transgo comes with, but i used a baumann engineering kit on my explorer (almost the same trans, and the direction are for both the AOD, and AODE).
Took me 4 hours, second time i helped someone, took 2 hours.
Snap ring pliers were a MUST.
Takes no special skills, except patience and good reading.
In the baumann, you don't have to mess with the check balls, you can leave them in. I'm pretty sure in the Transgo, you have to move or remove some.
Remember if you mess this up, there is NO practical way to reverse the drilling you do. And a valvebody is $300+ from the dealer.
Supposidly a ball pein hammer will close a hole, but i wouldn't consider that an option.
It's a worthwhile mod. I actually have fully rebuilt valve body with a brand new TransGo in it that has never been used it you are interested. All you would need to do is drop the old one and bolt this one in place. It also has a high pressure boost valve which can be swapped out for the new stock original if don't want to run it with the shift kit and it has a new tv plug as well. Shoot me a pm if you are interested.