Bike More.
Work on Swim and more importantly Bike Pacing
Work on Bike and Run nutrition
Work on running strong (not fast). Build volume through frequency (run 5-6 X's per week) Train in the hills and rolling terrain. Do some trail running. 40 to 50 miles (edit from: 30-40 upon reflection :-) a week with proper bike training/pacing/nutrition there shouldn't be a problem to run 3:40-3:45.
Work on Swim and more importantly Bike Pacing
Work on Bike and Run nutrition
Work on running strong (not fast). Build volume through frequency (run 5-6 X's per week) Train in the hills and rolling terrain. Do some trail running. 40 to 50 miles (edit from: 30-40 upon reflection :-) a week with proper bike training/pacing/nutrition there shouldn't be a problem to run 3:40-3:45.