I am in early planning stages of an expedition vehicle build and I've wrapped my head around the body, electrical, subrame, interior cabinets but I'm not finding much on plumbing design with fresh / grey tanks outside or at least through the cab. Trying to keep weight between the axles with a rear dinette. I don't want to throw the water tanks into the benches behind the rear wheel. So I'm looking at how to do "saddle" type tanks below the habitat in front of the rear wheels, but not finding much on do this with a subframe. Any resources or guides would be appreciated!