ok, now I am WAY behind so I didn't want to read too much, dh and I just watched episode 7-8 on Netflix - the one where the little boy gets shot, and the little girl is missing. But alll I keep thinking is WHY don't the go to an RV dealer and take a good RV, and why aren't they heading to supertarget/superwalmart? What about a boat - an island.... or getting somewhere defensable! Ah it's infuriating they just keep driving into Atlanta and out.
The stores are mostly empty, from people storing up in a panic when the epidemic started, through whatever was scavenged by survivors after the walkers took over. Presumably, the same thing happened with RV dealers. Those kinds of places are also in heavily populated areas, so it's likely that they're overrun by walkers and impossible to get to for whatever's left.
Atlanta is completely overrun. People were headed there because there was a refugee center, but the zombies took over and now its not safe to stay there. You'll see in another episode this season what else happened to Atlanta when it fell, along with what it looks like now. They can't stay there.
Boats and islands are tricky (just watch the end credits of the Dawn of the Dead remake - yikes!). There's no guarantee that boats are left at the docks, since people probably ran to them. Plus they're a big group of people and they'll need plenty of food and gas for probably more than one boat. And if they get to an island that's overrun (again, Dawn of the Dead end credit scene), they're screwed.
Where they go and what they're able to get are really dictated by where the walkers are, unfortunately.
Plus, by the time you get to the end of season 2 and into season 3, you'll see that zombies aren't the only problem...some of the people left behind aren't so nice either.
