I'm running my first Olympic triathlon in Lanzarote next March with friend Ivan Shyr at Sussex Place Ventures, and have been focusing on endurance and cardiovascular capacity these last few months.
Some of the constraints and assumptions I have:
Below is a training schedule I've put together, combining elements of high-intensity interval training and Crossfit to maximize cardiovascular improvement, and swimming to improve my familiarity with the sport. This is all a hypothesis to get to a minimum level of fitness - as the new year starts my training will have to ramp up as well as having coaching help.
In total I work out 5 hours a week, 1 hour to cardio improvement, 1 to swim, 1 hour to run, and 2 hours of general overall fitness, transition, and endurance.
 The importance of sleep shouldn't be under estimated. I try to get at least 8 hours on Wednesday, Saturday, and Sunday nights