We all approach ultra distance events a little differently, so what works for one person might not work for you. That said, there are some proven elements of training that you should include: build base, then build speed, then put the two together.

Whether your train by miles or time shouldn't make too much difference. What will make a difference is training to simulate the stress of your event. Also use training to dial in your equipment, bike fit, clothing, nutrition, etc. My philosophy is typically to push the limits in training to find the weak points and potential failures before the actual event.

I've competed in a couple of double century events already this year, with a couple more to go. I used a 16 week plan to prepare for the first one, although I had a decent base over the winter. Given your current 150-mile weeks you're in a pretty good position to start.

I know there are many people who compete successfully with lower saddle time than I have. I just haven't figured out how to do that plus I like riding my bike, so 15+ hour weeks are ok for me. This is not a constant, however, and I definitely subscribe to a cyclical plan. Instead of the usual 4 week cycle (3 weeks building intensity with 1 week recovery), I prefer a 3 week cycle. I've found that a 4 week cycle can put too much stress on my body and a 3 week cycle with more recovery actually allows me to get faster/stronger. Something to at least consider.

I also find it very helpful to schedule back-to-back long days. My typical week includes a long, hard day followed by a long moderate day. The hard day may be a fast club ride, a 200k or 300k brevet or something similar with multiple red-line efforts and on-bike recovery. The following day typically is at tempo and does not include the red-line efforts. I also like a mid-week effort; this may be a 60 minute time trial, or two 30 minute efforts within a 2 hour ride. (Back when I was faster my coach would schedule up to six 20 minute max efforts at a time.) The key is to put yourself seriously into the red. Allow 2 or 3 days for recovery, then repeat.

When I'm training specifically for speed, my schedule looks more like this:

- Day 1: 2 x 20 minutes @ lactate threshold
- Day 2: Recovery
- Day 3: 15" on/15" off at maximum speed. Do 4 sets of 10.
- Day 4: Recovery
- Day 5: Medium length ride @ tempo
- Day 6: 6 x 2.5 kilometers at TT pace. Recovery interval @ 3 minutes. 2 sets.
- Day 7: Date night

I do not think I'm particularly talented on the bike, but I am very focused on doing the work. I'm a grimpeur not a rouleur, so I make a point of riding rolling hills in training (the old saying, "train your weaknesses and race your strengths").

A double century is never an ice cream ride, but riding to finish and riding for time are two different things. If you finish but still have some dissatisfaction then you probably have what Carrie Cheadle refers to as a "secret goal". Acknowledge your goals and train accordingly... and have fun!