Its alot easier to replace the outer sections and braces then doing the whole floor. We do floors and rust repair in all vehicles not just trucks. Send some pics. In my opinion if you have to do the whole entire floor you may want to question wether you should even use the cab at all. How is the rest of the truck? It is not an easy job and it takes alot of time,space and equip to do it CORRECT. If you are looking to do a Show truck I would replace it. We sell the floors also but I would find a place to go pick one up. Their are many companies selling the floors.
its alot easier to weld the cab supports in then all the welding you will do to put the whole floor in.