The least labor intensive option for waste disposal is to install a macerator pump and a hose long enough to reach the toilet. I'm assuming you would have a generator/solar to supply 12V power.
Otherwise get some 3 gallon buckets with screw on lids, and dump a couple every day and more if needed. 3 gallons is a reasonable weight to handle without making a mess. You could get a wagon or hand truck to haul them.
For water supply, again some buckets that you could haul to/from the pump in your tow vehicle. In my experience you need a wide opening like on a bucket, to work well with a hand pump. Rig up something like a milk crate to set them on so they are close to the pump.
You could then use a 12V transfer pump to pump out of the buckets into your fresh water tank, instead of trying to pour into the tank.
Obviously keep your fresh water buckets clean and sanitary. Maybe get white ones for fresh water and some other color for waste disposal.
Single empty-nester in Middle TN, sometimes with a friend or grandchild on board