I'm training for the Half distance this year. Currently, I have three key workouts per week:
1. Long bike (currently at 3 hours, working up to 4) Saturday or Sunday
2. Long run (currently at 90 minutes, working up to 120) Wednesday or Thursday
3. Tempo brick (90/30 minutes) Monday or Tuesday
I fill in the rest of the days with whatever workouts I can. Seeing as the swim is only 10% of the total race time, it's on the backburner for the time being.
When the races get closer, I will get more strict with my workouts. But for the time being, this works well for me and I can feel myself getting into better shape and gaining endurance.