As for the water tanks, I did a writeup with pictures on how my tanks are plumbed here:
As for the propane tanks, the auto-changeover is the only way to go. Just don't get surprised with an empty tank like I did. I don't know how long the "primary" tank has been empty, but I just noticed it last time we had the trailer home. I dismounted the tanks (so I could take the empty one to be filled) and checked the level of the second tank, and it was pretty full, so it couldn't have been too long. But just keep an eye on that indicator so you know when your "primary" tank is empty.
Also, keep an eye on your propane pigtails. I've had to replace both of mine. One was actively leaking (replaced under warranty), and the other was either leaking or close. I didn't bother checking the second one for leaks, It didn't pass a visual inspection, so I just replaced it with an upgraded part (of course).
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!