I think the most important section of a race is the one you can improve the most in. For example, I am a fairly stron swimmer, and would probabaly only improve by a few minutes if a really trained hard for the swim. On the other hand, I can probably shave 10+ minutes of both the run and the bike if I could just get off my ass and train hard. It sounds like putting your time into the run might have the biggest payoff, Cadence.