Our NE Florida LF group is planning an outing to Cumberland Island, Ga December 2nd (a Saturday). This would be an all-day outing (unless you catch the late morning ferry, see below); so food/water would have to be brought along. Also, if weather conditions for that day include rain or high wind, don't recommend the trip. The Island is probably the most photogenic spot in NE Florida/South Georgia area with its Dungeness Ruins, dunes, wild horses - see National Park Service site for more info.
There are at least two ways of getting there. If you stay at the GreyField Inn, there is a private ferry from Fernandina. Or you can catch the ferry from St Marys, Georgia. During the Winter the St Marys Ferry runs two trips to the Island (9 & 11:45 AM) and one return trip (4:45 PM). You need to make reservations in advance since the Ferry can get booked up.