So this is what I ended up with. Very messy.
I had to add a second spur to allow the second tank to fill faster. I was just letting it flow through the pex that tís I to the pump intake and it was taking forever.
I also added a diverted valve so I use water from one tank at a time rather than both at once.
All of this made me afraid that my fittings would get hit and I would break a fitting or worse, a bung.
So I made platforms that go over the hoses so we can store junk without killing the plumbing. They just lift out, but do a lot to easy my mind.
Drain valve for purging tanks.
By the time I finished this the vent lines started looking vulnerable.
And yes I used great stuff to attach the vent line to my existing spray foam. Ugly, but will be hidden and secures well without puncturing the seal of my spray foam.
I replumbed the vents using pex and finding less vulnerable paths.
Then I built boxes over the bungs to keep them safe.
While in the area, I labeled all my electrical plugs.
Gonna have to come back with clear tape to get the labels to stick.
All in all this was a learning experience. I hope it works out, but I feel like the whole tank/pump situation is not elegant.
It all works though and no leaks...
Getting started on propane now.
Looks like Iím going to be able to reuse almost the entire system that came out of the RV with little modification.