I agree with everything except for the battery issue. I have the same boat for 23 years and now on my second set of batteries both deepcycle and regular starting type and have yet taken them out for the winter. I ensure that I have a full charge on them at haulout time at the end of October and monitor them a few times during the winter and they are ready to go in May when I launch with no further charging.

It does get cold here in Canada but even at -40F tehy seem to do just fine. I don't take them out of my cars either. Good luck!