Hi Mike,
You can start the plan now and follow weeks weeks 1-8, then restart the plan at week 1 on April 27 and follow all 12-weeks to a peak at HC100.
Another option is to follow the first 8 weeks of our Masters 40+ Mountain Bike Base Mountain Bike Training Plan then progress on to the 40+ Masters 100 Mile Mountain Bike Race – Personal Record Plan on April 27.
Coach Lynda