Century Ride PASKENTA Ride/Race

I have opted in to do a century ride.  It is in 3 months.  I have never ridden 100 miles.  Infact the closest I've been to riding 100 miles is about 70 and that was once.  We did climb about 7,000 ft or so but well this should be interesting.  I figure the best way to train for a century ride is to ride centuries but I don't think that's going to happen for me.  I'm excited about it, and hopefully I'll be able to stay excited and ride quite a bit before then.  It has about 1,700 ft of climbing which shouldn't be bad at all but it does have a 4 mile strip of gravel road!  One of the first R.A.C.E. events I did this past year included a section of gravel road and let's just say I wouldn't call it fun.  I still haven't decided if I'll do that race again this next year or not (probably will).  That was a crazy race.  My saddle came loose on the second to last lap which made for a rockin' ride.  The good part was that I got a new(used) saddle after the race.  Here is a link to the PASKENTA ride/race from the R.A.C.E. site where you can check out pictures from previous years and the map of where the ride will go.  Apparently 200-300 people show up if the weather's right.  The biggest plus - It's Free!

Any comments on how to prepare for a century are welcome.

Here's a nice shot of the gravel section of the PASKENTA ride/race that I found on the marcpro-strava cycling teams site : http://marcpro-strava.com/blog/2013/01/24/2013-paskenta-riderace-this-february-3rd/  Looks like they came out to ride.