manual trans to auto swap

I have a 95 sierra with a 4.3 and a manual 5 speed. I'm considering swapping the trans for a automatic ( possibly 700r4). The question is how much trouble am I going to run into. Will I have to deal with computer issues and how much trouble will I have making it a column shift or will I be better off just installing a floor shift. The manual trans is tired and I am soon needing a clutch, so I thought as long as I'm gonna go through all this why not swap an automatic in it. Any help will be greatly appreciated.