I really appreciate the thoughts guys. Many minds make great decisions.
My intentions for the truck are to wheel it....try not to hurt it or myself with my limited wheeling experience, and I want it to be safe for anyone in it. It has hacked on quarters, and some floor patches in the front.
It is rusty especially compared to western bodies, but not as bad, compared to most midwest/northeastern bodies that have seen year after year of salt exposure. It is no cherry by any means, but its still a safe truck, especially with the cage and body tied together.
The floor is intact throughout the whole bed, although it does have a few minor perforations from trapped moisture areas like the rear of the floor pan @ the tailgate. It is solid from the wheelwells forward since I redid the wheelwells for the bigger tires and rear axle being moved back 4", the stock rusty wheelwell seams have been cut out to solid floor, and rebuilt with the new wheelwells, My intention is to raise the floor from the rear seats to the back of the floorpan @ the tailgate, 2" and to strengthen the body mounts just in front of the axle, and reinforce the floor and have an opening just big enough to pull the tank out from the top if necessary. So a 2'x2' opening between the framerails would be framed out with the angle iron and it would support the tank from there. I have looked at Pauls rebuild of his floor, and would consider the same type of replacement, and have seeked his opinion on this as well, I do need some help here, as I've never tackled a floor replacement before, but feel I can do the job with some direction.
I'm not sure what to do about the rollcage down tubes at the tailgate as they do sandwich the body in the cage construction.
So picture if you can the floor raised 2" from the rear seats to the tailgate, from one wheelwell to the other, then make an opening in between the framerails big enough to support the tank and to get the tank out of from the top....
The two shiny bolt heads in between the fenderwells are where the bodymounts are starting to push up the floor pan, so from in front of those ~6-8" to the rear tailpan is the area of concern for now.