I have a 30 gallon tote with 2 wheels and long handle with a loop on the end (slips over a trailer hitch ball). My black tank is 40 gal, grey tank is 60.
I try to dump the black water when onboard tank is 3/4 full so I can get all the black water in one run. NOTE: the first few times I dumped into my tote I found the entire process absolutely repugnant, as you can't help but get a good look at a few floaters when you remove the short sewer hose from the top of the tank before you seal up the inlet for transport to the dump station.
Once sealed I hook the looped handle over the trailer ball on my VUE and slowly drive to the dump station. Never exceeding walking speed. BTW... When full 30 gallons of Cr...Stuff is HEAVY!!! Don't forget to take your short sewer hose with you. You'll need it at the dump station.
When I get to the dump station first thing I do is unhitch the tote and roll it into position next to the dump hole in the ground. Then I remove the inlet cap (now the outlet cap), and attach the short sewer hose. This is another opportunity for a floater to rise to the opening and say Hi!
Attach the short sewer hose and shove the loose end down the dump station hole. As my inlet/outlet is on the top of the tank, I then lift handled end to start the flow of liquid er.,al., into the dump sewer. As the tank drains I lift the handle end higher and eventually I end up with the tank completely inverted (the inlet/outlet is pointing down).
Once the tote is empty, I'll use fresh water from the dump station and put about 5 gallon in the tote, put the lid back on, then slosh it around and then dump that water.
I then return to the motorhome to dump and transport the grey water. Dumping the grey water also washes out the inside of the tote, and when all done I do the fresh water rinse one last time.
Following this procedure I have never had a problem with it smelling at all. I keep mine store in one of my basement compartments and I never have any offensive aroma when I open the compartment door.
Hope this helps you to understand the process. Bottom line, it's not a pretty job, but it beat breaking camp to drive to dump station.