Congratulations on the promotion-- there's a lot of stuff to chase down there.
There are striped bass in the Savannah river, redfish in the marshes and a mess of other inshore stuff including spanish macs and weakfish as well as offshore stuff like cobia and jack crevalle.
As far as gear goes, it will depend on what you'll be chasing-- For stripers in the Savannah River the most most fly fishers use pretty heavily weighted fly lines to get deep and large flies 5-6" long-- you could get a way with an 8 or 9 weight to throw 300 grains but to throw heavier, say 500 grains to get big flies down in heavy current you'd want a 10 weight.
Redfish typically 8 or 9 weights are used -- (big fish, heavy current and strong winds) but you could occasionally get away with much lighter stuff down to 6 weight if you had a decent reel
Spanish macs, weakfish (spotted sea trout) and other stuff 7-8 weights are fine, but again you'll often run into them while fishing for reds, so a heavier 8 or 9 is often used
Off shore stuff like Cobia, jack crevalle, mahi etc 10 weight. These are pretty powerful fish, and you'll want a rod with enough backbone to fight them. Because these fish are often caught in deep water over wrecks you'll want the lifting power of a 10 as well as it's ability to throw heavy grain lines. The reels matched up with 10 weights also tend to have more backing capacity than a typical 8 or 9 weight reel (unless you use gel spun).
An ideal might be two outfits to cover all the bases-- an 8 and a 10 weight, but you can of course prioritize based on what you'll be most likely to chase, and based on what kind of fishing is hot when you arrive--
And don't forget the freshwater stuff you already have-- in addition to trout on some of the southern tailwaters, you'll also have plenty of opportunity to chase bream and bass in fresh and brackish water.
Flies are pretty basic and easy to tie-- you can get pretty far with a fistful of 1/0 deceivers and size 2 clousers to start, but you'll eventually want to add other stuff based on the preferred/available bait for the fish you'll be chasing crab flies for redfish, as well as adding some top water stuff etc.
There's an FAQ on surf fishing gear if you're going to be doing a lot of wading, and some of the stuff will be useful for fishing out of boats as well. The link addresses items useful for the Northeast Surf (where fishing often involves standing on rocks among crashing waves in the middle of the night). You'll probably be sight fishing in more sheltered waters but some of the info might be helpful: http://www.theflyfishingforum.com/fo...tml#post307082