John,

Does your '48 have a plywood floor (I think that all AD Suburbans do but am not certain).

The only way to remove (without cutting the floor) the plywood floor from an AD Suburban is to remove the "side rails". There are at least 30 spot welds holding each siderail to the inside (rear) wall. I spoke with someone who has done it but I decided to leave mine in place and replace the linoleum mat (I think it is made of grooved linoleum).

As you mostly have determined, it is not possible to maneuver the floor out (in one piece) through the bottom (even with the body off the chassis).

Tim