Shower and Toilet without dumping

Hey guys, this is my first post here on tnttt.com! I've been reading on several different posts about toilets, showers, and plumbing systems in general. I've got a conundrum though. I want a shower and a toilet in my trailer. No problem there, but I don't want to have to search for a dump site and pay dumping fee's. I'm a huge fan of composting toilets. That'd be ideal, but being on the road, this wouldn't be viable. I've seen a few post about them in TDs, but i'm not sure about the composting part of it. And then there's the grey water situation. My question is: Has anyone made or thought up an alternative for all this? Maybe a mobile composting toilet system? The idea is to get the trailer as off grid as possible, minimize living expenses, and maximize a travel budget without compromising(too much
) on a what my partner considers necessities. Maybe it's something that can't be done. Maybe someone has links or knows where discussion on this topic is had?
Thanks!
-Dreamwalk

Thanks!
-Dreamwalk