I would think even a 40 dollar 7w solar panel, battery clipped and tucked somewhere sun shiny would suffice if you can't get a plug in.
I'm the guy who leaves my fridge running all the time. (just a tip if you're looking for a fast get-outa-town when the month is over.)
Put some bleach in the fresh water tank.
Open the roof vent in the bathroom.
Put a couple of tablespoons of veg oil in the water filled sink traps and the toilet to keep evaporation down so the black tank doesn't shmell you out.
(I'm thinking out loud here, and have never tried this, but do we thinka layer of some saran wrap floated on top of a bit of water and oil in the the toilet would, due to the leakage of the ball, form a kinda vacuum seal once all the water/oil leaked past the valve?)
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