having ridden those roads a lot, no question. TT bike.
Now I'm super-torn. Your comment gave me confidence that riding a TT bike is the key. Then a friend of mine and I floated the question to a former pro cyclist with some tri experience who has also ridden those roads, and he said road bike with clip-ons is the no brainer. So, I now have two opposing no-brainer views. His thought was that the road bike gives the best of both worlds for the technical nature (up and down) of the course.
You are the true TT guy, so I am leaning heavily your way on this. Plus, I bet all the pros and most of the top AG people are on TT bikes. It's my first race at this level, so I want to maximize the experience.
So, I will probably do a couple test rides on a similar course near Greenville to see how my TT bike goes. If I am comfortable on the uphill and can stay in the drops most of the time on the way down, then I will stick with the TT bike. Otherwise, I will do a total reconfigure of my road bike.