BRAG went over Unocoi Gap this year, from Hiawassee to Dahlonega. It was a very tough 5 to 6 mile climb, followed by a really fast 7 or 8 mile downhill. The total ride was just under 50 miles that day. The scenary was spectacular. The downhill part was like riding a roller coaster, but with you being in charge. Coming into one of those mountain switchbacks at over 40 mph was a pretty exhilerating experience.
That route was a good one. Check the BRAG.org site and see if you can find a map.