Below is a sample triathlon workout, I made for myself a few years ago when working out with some Naval Academy Tri-athletes.  If you are considering a triathlon one day, you can use this type of training plan and adjust the distances as needed. With your goals a steady increase in intensity training is recommended with little 2-3 week tapers prior to every race.

For the first month, I recommend the following schedule; 

Swim   3x per week:  Two - distance swim of freestyle 2000m (500m hypoxic thrown in)
                One - interval swimming with timed paces and increasing speeds (see below)

300m choice warmup
4 x 50s one easy, one pace on 1:15
1 x 300m at 65% on 6:15
2 x 200m at 70% on 4:30
3 x 100m at 75% on 2:15
4 x 100m at 80% on 2:15
1 x 200 Pull breathe 3,5 by 50s
3 x 100 take 4 breaths first 50, 5 the second 50.  Long smooth strokes.
100 cooldown
total yards = 2400

Run     3x per week:   Two short runs of 6 miles / one long run of 10 miles (Saturday) after 20 mile bike 
(triathlon slang BRICK = Bike + Run + ICK (because they are hard and should be done at great intensity and timed…)

You want to do the BRICKs in Bike – Run order to get accustomed to the Bike - Run transition…
Work on speed from Bike to Run as well…

Weights – 3x per week