I know that my 5.9 cummins in my 90, will go anywhere any of my other full size gasser friends trucks will go. It will wind in the mud with any bigblock for trail duty, and I can wheel a whole weekend on a few gallons of diesel. My buddy's with big blocks, and even small blocks, they are dumping gas in every night, sometimes even in the afternoon to finish the day.
After seeing mine work, and wheeling friend took his BBC out and will never go back. His tuned 5.9 cummins has never been a slouch to his BBC.
All that being said, I think a 5.9 is going to be a little much for the above said chassis. I think the 4 cylinder B will be sweet.
