From the Internet I learn that there are very substantial reductions in the
price of round-trip "excursion" fares -  i.e. from Nantucket to the mainland
and return, for "part" time "residents" (?summer) as well as year-round
residents, with no definition of "resident" and no specification of the 
maximum duration of the "excursion". Thus like much else on the Island,
it's arbitrary politics; formal inquiries in advance would be counter-
productive, and would lead to arbitrary curtailment. My strategy would
be to appear at the SS Authority ticket counter on Nantucket (not Hyannis)
with tax, light and telephone bills to prove I was a "resident", and 
negotiate the length of the "excursion." 

The uncertainties and variables of our Nantucket future(s) are too complex
for e-mail. We should discuss them face to face after you've returned, 
or by 'phone, if you're impatient. You have, as Michael Burns put it, 
"the right of first refusal" of any or all the many initiatives required 
to complete the house.

I hope you are well and that you are surviving Florida with your humor intact.