So to battle this its really important to get in short intense rides, two hours or under, to work the anaerobic systems and recovery inside of those efforts. Working these workouts will help put more "bullets in your chamber" during a race, or make sure that you have the snap when things start to heat up.
The workout I am going to show is one of the best for the race season (this was highlighted on vs. with Chris Carmichael) 30 seconds on, 30 seconds off. Robby prescribed a warm up into a 30 minute straight block of 30s on/off (30 intervals) with a minimum average wattage of 350, 20 minutes of recovery then 10 minutes of 30s on/off with a minimum average wattage of 400.
So when you put that on screen it will look crazy
Here is my download

After a block of time off this was not so much fun, my numbers were pretty low for me in terms of where my heart rate was, and I was pretty close to throwing up about three times. I kept a very high cadence and did a majority of the intervals seated to also help with some core maintenance on the bike.
If we had some hills here, this workout is perfect for climbs, it would also facilitate maintaining higher watts since gravity is on your side. Unfortunately, Florida has rollers at best. So you just have to put your head down and go.
Feel free to comment with questions and I hope to make this blog a tool and resource for all