If it were me, and given that I've had a professional survey done, I'd do the following:
1) Wait until spring, like you said. That will make it a lot more enjoyable and I think the weather is more predictable.
2) Buy an engine. This gives you so many more options that it's amazing. Waiting 12 hours in a lull versus moving along at-will. I know we are all about sailing here, but it's also fun to motor along when the water is glass-flat. Get one with an alternator (battery charging) if possible so you can keep the battery topped off for VHF radio, music, and lights. It also adds a lot to the safety factor in my humble opinion (IMHO), since it allows you to more easily set your anchor, correct a mid-night dragging anchor, get into inlets, motor down the intracoastal waterway (ICW), there's probably 100 reasons why having an engine is better. If you are retired then you can do the trip in 100 days and not care about it. Some people would really enjoy doing it without an engine. But otherwise - and that's a big otherwise - get an engine. New is better than used since breaking them in properly means running at 25% power for longer than your average person will have the patience for. (Whine, whine, I paid a lot and I want to go fast NOW.)
3) Take a Power Squadrons course or other navigation and rules-of-the-road course. They are offered everywhere and taught by volunteers who will take the time to make sure you know how to navigate. Because you can't just pull over to the side of the road when the crap hits the fan. And you'll scare yourself in some way 3 or 4 times on such a long journey. When it hits the fan, it's better to quickly go "oh yea, I do xyz when this happens" and quickly get out of scared mode and into fun mode (or at least "this is ok" mode). There are also BIG THINGS out there that take several miles to stop. At a Power Squadrons course, you'll learn to recognizing them (day or night), know where to expect them to go next, and stay out of their way.
Here's one local contact for your area. There are probably others within driving distance if you use google:
Lake Hartwell Sail & Power Squadron
WebSite: Lake Hartwell Sail & Power Squadron
Contact: P/C James Bertram Baxter, AP
Location: Greenville, SC
Centered around: GREENVILLE, SC 29607
They have a basic class and then more advanced classes. See if you can take one or two of the advanced classes. Check this out:
America's Boating Course it's as easy as ABC
Boating is Fun...We'll Show You How. Our next Basic Boating Skills Course will be held 7, 14, 21, & 28 March 2011 with optional on-the-water instruction on March 19 or 26, weather permitting. This Class will be held at Messiah Lutheran Church in Mauldin, SC. To Register for this class click here to download a Registration Form and mail per the instructions on the form. Email Lake Hartwell Sail & Power Squadron for more information.
I believe the list of their courses/seminars can be seen here
4) Go sailing with someone who can show you the ropes. This can be on their boat or yours. If you spend some time with someone who has sailed a lot, you'll learn a great deal. This would augment the classes very well.
5) Take a lot of local day sails and overnight sails to get used to the boat before you make the big trip. You may want to fix something or add something, and having stores nearby -- and your car to get there -- will make it a lot easier. You may find the bilge pump is broken, or the battery no longer holds a charge. Or you want to add a reading light, or a second anchor, or a small grill, or an alcohol stove, or a chart plotter, or a couple flashlights, or a dinghy, or a flexible solar panel. The list is long and half the fun of owning a boat is tweaking things to be the way you want them to be. A little expenditure can make your time afloat more to your liking.
6) Go. Given the above, check the weather each day and go! Enjoy the trip because you are well prepared. Post an ad for crew wanted here. We have a lot of members that love to take trips. Some are building sea-time on other people's boats to get their captain's license, other just want to sail. Remember your camera and post some pictures here.
Most importantly, keep asking the questions. That's what everybody does here.