I have about 7 weeks, untilI take part in a Fondo event roughly around 85 miles with not much climbing due to being it Cambridge in the UK. I have a releativly good base level of fitness but only have managed 2-3 hours or so in the bike in the past 4 weeks due to life.
I am eending on just doing a General Fitness plan and topping up with any Endurance rides 2 hours and greater when time allows.
@MrHyde based on your available time and what you have been able to accomplish the past month, I believe the General Fitness Plan would be a great option. The plan has 2 key workouts a week and if you can get in some extended Z2 and Z3 rides on the weekends you should be set. I suggest making the week beore the event a little lighter.