Please don't misunderstand: I'm not advocating anything, not even making 
suggestions, but merely trying to catalogue the many fascinating
Nantucket options open to you.

You can sleep in the van with the seats removed, as Tim and I slept
in our respective vans for several weeks until the house was enclosed.
Through an extension cord from the house, you could get electricity for 
your breathing apparatus, for an electric heater and for an electric
blankets. With an air mattress and a sleeping bag you might well be
more comfortable in a warm van than in a cold house. You could use
a camping toilet which you could empty into a suitable subsurface pit;
you could rent a portable toilet. You could drink bottled liquids;
you could retrieve water for washing from Long Pond (as I did for the
ultimately faked soil permeability tests.)

You could respond to charges against you, by stating (truthfully) that
you instructed me not to connect the pump to the pressure tank, that
you instructed me not to install a toilet, that you instructed me not to 
connect a shower, that you instructed not to connect a sink, that you 
instructed me not to "occupy" (whatever that means) the house without 
an occupancy permit; but that I was 88 years old and so demented that 
I could no longer distinguish between the Nantucket authorities and the 
German Nazis of my childhood; that you were not, and could not be held 
responsible for what I did in consequence of my insanity.