Kenny's boat idea was actually a good plan.
While I don't think the group was likely to find salvation in the boat, which is what Kenny seemed to expect, I think an island off the coast would make a perfect place to bunker down assuming you can find one with some shelter.
Many of the islands off the coast of Georgia and South Carolina are likely to either be completely free of, or mostly free of walkers. The ocean would also be a far more effective barrier against those monsters than any man-made structure.
You can also use the boat to potentially travel hundreds of miles unlong the coast line and up rivers, raiding deserted farms, box stores, towns and cities for food and supplies like Vikings (not literally) whenever the oppurtunity presents itself. By operating in a boat you'd give the group a much larger 'territory' to scavenge than you would by operating on foot or in a car. Assuming you could scavenge enough gas to keep the boat running (and why couldn't you, considering the amount of territory you could cover) you'd have a very good set up. Of course supply runs would be as dangerous as always, but you could cover huge swaths of territory, and your home base would be much better protected than if you were set up somewhere inland.
I can't recall now if the found boat had a sail, but even better if you had a boat that could function by wind power as well as by engine.
Depending on how large island is and the quality of the soil, you may even be able to raise crops or livestock there, so long as you able to scavenge equipment (and farm animals) from abandoned farms. If neither of those is an option, you could create a greenhouse to grow some crops, while relying on the boat and the ocean's bounty to provide protein. An island has coasts from which to fish or crab, and the boat gives you potentially hundreds of square miles to harvest.
Using the boat, you could also access military bases which would have massive stockpiles of MREs (Meals Ready-to-Eat) that literally last years without spoiling, as well as huge stocks of military grade weapons (assault rifles, machine guns, grenade launchers, ect) and all the ammunition you could possibly need. Military bases would also have CS gas (the stuff you you see being used by riot police) and gas masks, which could be useful against potentially hostile humans, and things like flares (for signalling or night time illumination), compasses, maps, drums in which store water, shovels, sledgehammers, and other assorted tools, radios, batteries, field phones and communication wire, and claymore mines. The Marine Recruit Depot at Parris Island, South Carolina, is only about 45 miles from Savannah, Ga.
The biggest drawback for sheltering on an island off the coast, is that hurricanes or large storms could be dangerous. But since potentially lethal storms are usually years apart, I think that is a less pressing concern than walkers.
If you had been part of Lee's group, what would have been your plan?