No, Savannah is a cool town. Lots of good food and activities, beaches are close, fishing is good, lots of history, etc. I'm not intimately familiar with the crime dynamics, but my understanding is that it is hit or miss depending on where you are. Probably like most places, it depends on what part of town you're in.
In regards to "trails", you're pretty much SOL. There's plenty of dirt roads and muddy spots amid the pine trees, but nothing that I would call a good "trail" for a 40.
You looking to move into the city or one of the surrounding suburbs? I think crime is going to be the worst the nearer you are to Savannah proper, although there are some really nice spots in the city too.