I highly suggest a macerator pump - we've found them very useful and have them on both rigs (Sani-Con on fifth wheel, and FloJet for TC).
It's not something I do often, but I have dumped the tanks into pit toilets a couple times. It's probably frowned upon, and as such, I generally avoid it. If I have no plans to leave a site, it's a long round-trip to an actual dump station, and the vault is very lightly used has lots of visible capacity, are about the only set of circumstances I'll do this.
I guess your method might work, but I've never had much luck with garden hoses and those bayonet caps that have garden hose outlets on them. With a larger hose - or enough actual sewer hose - it would probably work fine.
Now that we don't have black tanks (we have composting toilets), I might dump a five gallon bucket or two of grey water in every couple days. Keeps us from having to move, won't overwhelm the system, and I don't feel as bad about it.
