I often stay at campsites without water, and worrying about making the water last for a week or so is always a major concern - if another person is with me, the concern is amplified. It's really inconvenient to hook the whole trailer up to just get 40 gallons of water or to dump the tanks.
So...what I did...
I bought two 35 gallon "poly leg tanks" that fit in the back of my truck. I labeled one "POTABLE" and the other "WASTE" for obvious reasons.
On the potable tank, I attached fittings to and valve attach a white hose, and I have a portable 12 volt water pump (designed for a sprayer, but rated for potable water). I put a bargeman connector (like the TM uses for its' lights and brakes) on the wiring for the pump, so I can run it off of the trucks' battery easily. It takes about 20 minutes to pump all 35 gallons into the TM.
On the waste tanks, I attached a 1 inch flexible hose to the outlet, with a valve at the tank end of the hose and another valve about 1 foot from the end of the hose (you can't have too many valves when dealing with sewage, and the final 1 foot section of hose past the last valve lets me make sure I can shove the hose down the drain station opening far enough to avoid problems). Obviously 1 inch hose is smaller than 3 inch slinky hose, so to solve that problem I use a FloJet macerator to fill the sewage tank, via a garden hose fitting I attached at the top of the tank. Anything that can flow through a garden hose can easily flow through a 1 inch hose. I also have a hose cutoff valve installed at both ends of this black, contractor-grade hose (you don't want leaks dealing with sewage!). The FloJet is wired into a bargeman connector, just like the fresh water pump. I haven't tried this with completely full tanks, and haven't used it on the black tank yet (less need to dump that tank than the gray tank), as I want to be very comfortable with gray water before I try it with black! But, preliminary work seems to indicate it works great.
The only thing that I haven't done yet is secure the tanks in the pickup bed somehow - I'm still debating the best way of doing that. 35 gallons of water is 280 lbs, so it's enough weight that it probably needs to be secured fairly well. Right now, they just sit loose in the bed.
I like this solution much better than portable water containers that I have to lift up to fill the TM, and definitely much better than the blue tote for the waste water. There is no lifting involved with this setup, and the tanks are much better made than any blue tote I've seen. I don't want a graywater or blackwater leak!
With a generator, these tanks, and the auto-switching gas regulator, I can go as long as I want without moving the TM.