I had the same situation with my 87 that had a 6.5T transplant. I am adapting it to the chevy automatic so that raised the price, but I am going to end up with about $3200 in the swap. However, I did get a great deal on a low mileage 6BT for $1150 so that helped with costs. As far as the installation it took two good days to get it bolted in the truck. Yours might be easier depending on how you do it. I had to cut and modify two cross memebers, so that took a little more time.It would be pretty much just a daily driver with some towing every now and then... I have been thinking about rebuilding mine, but it will be over $3,000 easily... i found a 91 cummins motor and transmission (with radiator, wiring harness, etc) for half that price... just not sure how complicated it would be to throw in the cummins engine and dodge trans in my pickup.
From all my rambling I hope you can discern that I would recommend the swap, but just plan on some time and unexpected expense to complete it.