Are these races too close together to give me any sort of recovery? Will I be spent and unhappy racing back to back weekends and then again two weeks after that?
The challenge? The accomplishment? I want to do this because it is an opportunity to live life. The event is an indoor sprint triathlon. I get to experience the challenge on a safer scale.
This plan is designed to make you go faster. 3 workouts per week in each sport, 2 days of strength training and core work. The maximum volume is around 10 hours toward the end of the 12 weeks.
Since your “A” race is your marathon, which you stated in your question, this should be your main focus. I encourage you to taper a bit for the sprint distance triathlon.