At the next opportunity, you might consider installing a
90-gallon hot water heater. That's enough hot water "standing by" for up to three days.
Alternatively, you could install a standby
120-volt hot water heater in a capacity that the smaller-sized generators could handle.
On the other hand, the permanently-installed propane powered home systems are touted as a major asset in homes for sale: on an island, even more so.