Hah... okay yeah... there is far less space behind the tire than it appears in the picture I originally shared. On my 2007 3124 KS, it's 25"L x 13"W x 5"H. That would've translated to a ~7 gal tank... minus the volume needed for a vent on top. And the 90deg turn toward the drain would bring me too low to the ground... I'd rather max my ground clearance, especially right behind the tire.
So instead... I just purchased the Dometic 5000-M65 from Marinesan (
https://marinesan.com/5000-m65-serie...white-or-bone/).
I'm a super rookie at plumbing, so I'd be grateful for any direction about tapping into this complex system.
@larsdennert, I'm loving your take on shark biting into the water supply. Any additional pics or tips you could include would be much appreciated. Same for the vent out - I wasn't aware that the sink already has a vent out. I found a great diagram of the supply side (
https://www.trailmanorowners.com/for...ad.php?t=21050), but looking under the cabinet it's hard to tell which is which.
I haven't yet found a schematic for the drain side. It sounds like there, I will need to do some research on how to use ABS glue and ABS shavings to re-seal to the gray tank, and then fill in with standard sewer drain parts.