Mark, some great updates!!!
I am just going to make some general comments! You are pretty much posting about my home, the area where I grew up. I really wish I had thought to give you some input on things to do while you were in the area.
First of all, I am sorry you blew right through Georgetown and found yourself in the middle of nowhere.

You were so close to some things that I think you and your family would have enjoyed. Georgetown has been there since before the American Revolution. Lots of historic sites to see. One very big one is Prince George Episcopal Church, occupied at different times (obviously) by the British Army and the Confederate Army. Supposedly there are hoof prints in the floor of the church made by British horses.
Numerous Rice Plantations at one time generated a lot of income for the Georgetown area. The history is commemorated in a Rice Museum downtown. As an elementary school student, I helped raise money to create that museum. Georgetown is also the location where the Marquis de Lafayette arrived in the United States to provide support during the American Revolution.
There is a pretty good historic tour of all the old and historic places in Georgetown. They have also done a lot of improvements in the Downtown district, including a Riverwalk along the waterfront, and lots of shopping and dining.
Cadets from The Citadel were the first to fire upon Fort Sumter. That is where Matthew graduated from before entering the Navy. It is a great college campus to tour, and if you are ever in the area on Friday afternoon sometime, you need to take in the "best free show in Charleston" which is the military parade held by the Corps of Cadets, especially if you happen to be there when they fire all of the cannons, including some Civil War vintage cannons.
Another great place to take the kids sometime is Fort Moultrie, on Sullivan's Island; accessible from Mt. Pleasant. There are numerous guns from various times in history on display there. It originally had walls made from palmetto trees, which is why that is part of the emblem on the state flag. Fort Moultrie is just across from Fort Sumter, and you can get a really good view from there.
Love the report about the Yorktown. Wish you had toured the USS Laffey. It was the same vintage and type as the destroyer my Dad served on in WWII. His shipmates have had a ship reunion there, and my Dad got the chance to show my Mom where his bunk, and also his battle station on the fantail were located.
If you ever head back and stay in the area let me know and I will give you some more info of things to do and see that I think would be of interest to you.