No one has answered his question about mounting the toilet to the tank, and I'm curious too......how does it go in? I'll be doing mine later this year, and also want to know.
As for the vent, I guess a common vent exiting the roof is OK, but a good installation whether one or two vents through the roof doesn't matter. If you have a good roof seal, then no leaks.
I'd still worry about gas from the black tank getting back through the common vent line, p-traps or no p-traps. I'm planning separate vent stacks.
comes to mind:
where in the tank you attach the toilet.
I'd think in the CENTER of the tank, as it's in a position to resist surges from driving/stopping the bus. Less pressure, less chance of splash or back flush.
I've recently become acquainted with someone that sells RV's for a living in RI, will be going down there in a few weeks to peek over the shoulder of their shop guys...I want to learn more about stuff like slide-outs, plumbing on RV's, electrical systems and the like.
ALthough I understand slide-outs have their share of problems, It's an interesting solution to space concerns.
I have to say I was NOT impressed with an RV a friend rented last year, the coffee maker (and a couple other things) wouldn't work, and I couldn't track down the wiring problem. What a mess! And this is a $150K vehicle? JUNK!