I am thinking it might make sense to buy Going Long, a somewhat scientific book about how to train for long distance endurance events. My approach of doing an assortment of runs, bikes and swims got me to a 13.28 Ironman but I don't think they will get me to sub-12. Without major structure I always gravitate to the comfortable burn (7 mile run, one hour ride or 1 mile swim). Hopefully this book isn't too scientific (e.g., percent exertion, workout zones) as those make me nuts.
I might also sign up for Pacific Masters, an organized swim team that meets at Koret Center. I swam half a mile on Saturday and my form is a joke. It would be seriously fun to be able to flip turn. I am going to try that this weekend with Ben and Sam.