I copied this from another forum. It's from a guy in Tallahassee, hence the reference to their local 'hills'.
It's very accurate. Things to add - the ascent of Hogpen has two downhill sections. Use them to drink alot of water/gatorade (the ascent is too steep for me to let go and drink...) and take every precaution on the descent of Hogpen as true. I've never been able to get up to 25 mph on that descent, but easily hit 38 mph on the descent of Jacks and Unicoi. If you can stay with your group, you'll appreciate it on the sections before the first climb, and the section from Wolfpen to Woody's, which is late in the ride and when you'll want/need all the help you can get.

Enjoy!

A DESCRIPTION OF THE RIDE

The course consists of an "approach" from Dahlonega followed by six climbs
with some rolling hills between the gaps. Each climb culminates at a "gap",
or mountain pass. The climb is named for the gap. There are refreshment
stops at each gap and an extra one about half way up Hogpen (gap 4). (There
may be more, but you won't need them.)

The approach is rolling, with some very sharp (but short) hills. It's
roughly comparable to a loop around the Havana Hills race course in Gadsden
county. You want to be very careful with your energy on these first few
miles. It is easy to get caught up in the moment and push hard enough to
effectively ruin the rest of the ride before you even get to the first
climb. Forget the group - ride your own pace and get warmed up. You
absolutely have to ride your own ride on the climbs anyway. Keep in mind: a
ride like 6-gap is more about energy management than anything else. You
have only so much, and you're going to need a lot of it on the latter part
of the ride.

Gap 1: Neels

This is a seven mile climb of moderate grade. Use it to get your legs and
CV system running well and to get the feel of what it's like to go up hill
for an hour. Watch your energy output rate (preferably with a heart rate
monitor) and keep it moderate. There will be plenty of opportunity to push
harder later in the ride, should you find the workout inadequate.

The descent from Neels is fast but straight enough to be relatively safe,
with good pavement. (For the 3-gap folks, the left turn to Wolfpen Gap is
easy to fly by if you are not looking for it.)

Gap 2: Jacks

After some fairly good Havana-hills-like rolling terrain, this climb goes
for about 3 miles at a moderate+ grade. This is where you get the
experience of making a long climb that is not the first long climb...

The descent from Jacks is long and moderate - let it fly. Beautiful scenery
and lots of free miles on this one. It takes you all the way to the start
of the climb to Unicoi Gap, no hilly stuff in between: just descend and
start the next climb.

Gap 3: Unicoi

Unicoi is about 3 miles of moderate++ climbing. The main problem with
Unicoi is that it is unshaded and can be very hot facing into the sun.

The descent from Unicoi is great. While the climb is relatively short, the
descent is over 10 miles all the way into Helen. The grade is steep enough
to be fun, but the pavement is good and the curves are well banked so again
this is not particularly dangerous. There may be a lot of traffic, the only
"down side". But the roadway is wide enough to accommodate autos and bikes
in most places. Stay aware of the traffic behind you.

At 1445 ft above sea level, Helen is the lowest elevation on 6-gap, thus
explaining why the descent is so long. (Dahlonega is 1880 ft.) And you WILL
pay a price...

Gap 4: Hogpen

This is the big one. Seven miles at a steep grade, averaging around 7% but
with some sections well above that. There are also a couple of false
summits. There's a rest stop at mile 4, with 3 to go. (The mile markers on
the highway actually correspond to miles on this climb.) Try to skip the
intermediate rest stop. If the weather is hot, though, you may need to just
get some fluid here.

The descent from Hogpen is dangerous. It is very steep. There are sharp
blind curves at the end of steep strait sections. The pavement is bad: old
chip-seal, broken in places, and loose gravel possible anywhere. The road
is narrow, and the camber of the turns is not adequate. The grade is such
that speeds in excess of 50 mph are possible just using gravity.

Someone said that if you don't brake, you won't flat: well, tell that to
all the people who have flatted on, say, our St Marks Trail. You can also
come up on wildlife, potholes, stopped leaf peepers, wet roadway, loose
gravel, pavement cracks, hickory nuts, crashed motorcycles, motorcycles
ascending in your lane, and any number of other hazards that require a very
rapid change of plans. Bad stuff CAN happen. I have personally seen
everything in my list above on the 6-gap course. It is unwise to descend at
a speed that allows for no margin of correction.

It is also unwise to brake too much, especially to ride the brakes. You
want to avoid heat buildup in your rims - eventually, this will cause a
blowout by melting your tube. (If you have plastic rim strips, failure will
occur at a much lower temperature. Change to cloth rim tape before 6-gap.)
And keep in mind: the heavier you are, the faster gravity will accelerate
you and the more heat you will put into your rims when you slow down.

There's no simple recipe here, just make sure you control your speed to
something that gives you some wiggle room in case of unexpected events.

Gap 5: Wolfpen

The second toughest climb on 6-gap. About 2.5 miles (depending on where you
define the beginning) with grades on par with Hogpen. The roadway is shady,
however, which is great if the weather is hot. (It's been known to sleet up
here, if the weather is wet.)

The Wolfpen descent is twisty but on good pavement with good camber to the
curves, so not too dangerous. It is often damp, though. Stay out of the paint.

Gap 6: Woody

The descent from Wolfpen takes you only down to Suches, home of the highest
elevation school in Georgia. Consequently the climb up Woody is a paltry
1.5 miles of moderate grade. From the top of Woody it's a 15+/- mile
descent of mild grade all the way back to Dahlonega. Try to have enough
energy left to enjoy it.

HOW TO SIMULATE A CLIMB IN FLORIDA

IMO: The only way to get a feel for climbing in Tallahassee is on a flat
road. We do not have seven mile hills. Hills around here are great for
building climbing strength and technique, but they can't give you a feeling
for the long sustained effort required for the climbs in the mountains.

Here is how to "feel" the climb to Neels Gap:

On a 20 mile stretch of relatively flat road, assume a climbing position on
your bike (hands on the top of the bar, loose grip, elbows out, chest open,
head up) and start a 20 mile time trial. Using your heart rate monitor,
maintain a steady heart rate at a sustainable level for the entire 20
miles. Let's say 85% of your maximum sustainable effort. OK, that's Neels.

Hog Pen: 30 miles at 90%

Wolf Pen: 15 miles at 90%

Etc.

The entire 6-gap effort can be simulated by riding about 130 miles in
Florida, making long sustained efforts of appropriate length. (Except, this
simulation is harder on your butt than 6-gap, and it's a lot less fun.
Plus, there's essentially no way to simulate the descents.)

ADVICE

It's all about energy management.

Stop at the top just long enough to get supplies. Rest on the bike going
downhill.

Be prepared for weather. I guarantee there will be some.

You can't have too low gears. Take all you have.

DISCLAIMER

Descending is never safe. Any time you are going 30+ mph in traffic there
is danger to be assessed and managed.