Hey Doug - if it is safe to say you might be targeting 3 runs per week, I would focus on the long run, one of the faster runs during the week, and one zone 2-3 run.
You could also take one of your bike rides and mirror one of the missed quality runs of the week.
But also mix it up and pick and chose run workouts that motivate you during each week of the program. The key will be to follow along with the weekly sequence and "building" nature of the program. In other words, dont skip around and move ahead.
Hope this helps and most of all, have fun with it and target a cool goal!
Eric - thanks for the quick response. You confirmed my thinking. I'm about to turn 60. Competed in triathlons for 10 years, including the Nice. But stopped in 1995. Calfs and hammies have periodically sidelined me since then. Born to Run and your Cool Impossible have me reinspired. Just did the test run and was surprised that the legs had some good memory left in them. I was thinking about your foot strike advise which really paid off. Thanks for the nudge.