[1retired06]

Not difficult if you are handy. I did the same thing myself two years ago, but with two black tanks and two gray. Posted exactly how I did it, should be somewhere in Search. Dropped the underbelly, did minor reroute of the plumbing, using heavy duty rubber couplings from Home Depot. l ended up with three pulls on DS, one on the ODS, all thru the frame, and none in the convenience center. Not counting materials and four new valve costs, took me 5 hours, so figure $500+ installation plus parts. Two plus years later, can still open with one finger, and if I have to ever replace a valve, will be easy with the couplings that are in place.