See a good shrink ;-)Work up to where you can do a 100 mile ride every weekend on Saturday with a 1-3 hr recovery ride Sunday. Slowly increase the intensity of the Sunday ride to 1 hour easy then 3 hours at tempo and 1 hour recovery. A couple weeks before the double, do a ride of about 8 hours with a 2 hour recovery ride the next day. On the long rides, eat and drink constantly from the time you start to the finish. Experiment with different on-the-bike foods and drinks before the double. There's nothing worse than having an upset stomach while suffering for 12 hours on a bike - trust me, I know. Bring an energy drink like Accelerade, a bar or two and a handful of gel packs. Besides food and drinks, most doubles provide E-caps or other electrolyte replacement capsules - take 1-2 every 2 hours, more if it's hot. Make sure you have good shorts with a GOOD chamois and a saddle that fits right. Use liberal amounts of chamois cream. Wear sunscreen.
On your short rides do as much climbing as you can - doesn't have to be fast. Most doubles in CA (except Death Valley, Butterfield and the Grand tour) have a minimum of 14,000 feet of elevation gain and the climbs are not spread evenly along the routes. Also, practice being smooth in a paceline. If you're wobbly or eratic, the other riders will get nervous or pissed and drop you. You need to ride with a group that you feel you can ride comfortably with. Do not go out with too fast a group, get in over your head and bonk after 50 miles.
There's too much stuff to put down here so if you have any questions or want to get together for training rides, shoot me an email. Right now I'm planning on the Death Valley DC in March, Mulhulland in April and Heartbreak in May and possibly Terrible Two in June. I would also highly recommend the Eastern Sierra which I think is in July. Visit planetultra.com for their double schedule and links to the other organizer's sites.
Good luck and suffer well
Posted by FFW a 46 year old Die-hard Enthusiast riding a throbbing saddle sore from Palmdale on 01/24/05