The manufacturers (and most of us) recommend not towing it more than 5mph.
If you are that far away from a dump station, then you need to either find another way to do it. Or figure out how to empty the tanks into the tote will its in the back of your truck bed. The tote filled is gonna weigh around 250lbs.
You can always, just hook up the camper and tow it down to the dump station and bring it back. We have a tote (Thetford brand) and have only used it for gray water, never black. I only want to deal the black water once and not twice. And hopefully it won't spring a leak or bust on you.