i was wondering how hard and what i needed to swap out my blown up 700r4 for a nv4500. i'm eventually gonna put a 12 valve cummins in my truck so i figure i would just get a good tranny now and put it behind my 6.2 and use it behind the cummins when i finally swap motors

The Dodge version NV4500 has a 1" longer input shaft than a GM version NV4500. If you do it now, and then later put in the Cummins and use the Dodge bell housing etc, you'll have to change out the Tranny input shaft with a Dodge one.
Or you could buy a Dodge NV4500 tranny now and buy an adapter plate from Advance Adapters that mates it to a std GM bell housing. It also happens to be 1" thick to compensate for the 1" longer input shaft.

it would be alot less work to just wait and buy a second gen dodge with the cummins and five speed for the swap. way way less money and work. i bought a rebuilt ctd nv4500 trans for my brothers pickup and with a good core trans it still cost 1800 bucks.

i know a guy with a first gen cummins motor that he said he would sell to me. so i figured i might just save my money up and swap the tranny and motor at the same time cause i have a 06 tacoma which i used to use as a commuter truck but i dont commute anymore so i think im just gonna drive that and swap both at the same time

http://www.dieseltruckresource.com/dev/index.php if you go to this link and go to the first gen area you can see how much more it cost to go that route. it can be done but the starter , adapter from engine to bell housing , flywheel and so on . not to stop you but just want you to know what your in for going this route verses buying a second gen with a five speed behind it. what ever your choice you will enjoy it.