Matt - I grew up in South Georgia and played Sea Island et al regularly (still do, occasionally).
At Sea Island...
Seaside is really good. Fantastic course for approach shots. I like Fazio's artificial mini-dunes (an homage to Chandler Egan?). The course has very few weak holes.
Plantation is a good course but a step down. I'd rather play Retreat, frankly - Love Design did a great job elevating the old Island Club to Sea Island standards.
Ocean Forest is a wonderful experience with several tremendous holes and spots. But I feel like it was a design miss. The bunkering is miserable, IMO. The first hole is the single worst opening hole I have ever played on ANY golf course, much less one as highly honored as Ocean Forest. Definitely a beautiful place to spend an afternoon (we had a bald eagle flying above us during our entire round this past January!).
I played Frederica for the first time on that same January trip. Secluded location. Unbelievable practice facility! The golf course is huge in scale, built on an artificially but masterfully contoured site. Many similarities to ANGC on a lot of holes, especially on the front side. Single-height mowing throughout. Huge greens. The back nine has a beautiful stretch through some marshland with scenic overlooks. 18th hole felt contrived to me. But again, an incredible experience. One of my five favorite clubhouses.
If you're in South Georgia, don't overlook Brunswick Country Club. Old Ross, redone by Love Design. Just a beautiful old club course. Well worth the time.
Neighboring Jekyll Island, with 63 holes, may be the best value in golf. Oleander is the strongest of the three 18-holers, but the don't miss is Great Dunes, the Walter Travis nine-hole course. With a little TLC, it could be spectacular.
I'll throw in one more plug for my old home course - and a true hidden Joe Lee gem - Okefenokee GC, approximately one hour away in Waycross. Built on sandy soil on the Satilla River, it really is worth the drive. A course that, if it were anywhere else, would get attention.
Have fun!