Have a 2014 376BHOK & I want to connect the waste drains. I had a neighbor camping last summer tell me he did it when he saw me dragging my sewer hose to the back lines. I was not able to check his out & have searched the forum with no luck.
I think that connecting the gray tanks wouldn't be a problem. I wouldn't connect the two black tanks as I think there would be too much level pipe run between the two would only lead to trouble at some point.
2010 Cedar Creek 5th Wheel 34SATS "The Beast"
2006 Ford F350 Lariat 6.0L Diesel
2003 Harley Heritage Softail "Hogzilla"
1988 Harley Softail Custom "The Fireman"
1986 Marriage to "Wifey" (patience of a saint)