That looks like a good program. It will more than adequately prepare you. Your bike will be fine. I've seen people on MTBs with knobbies, even unicycles. The instructions for the HARD rides may be difficult to follow. If the event course is nearby, you might want to drive it. Match the terrain on your HARD rides to approximate the event course and just go hard on the hills. If it's flat, then easy to follow the instructions. If your area is hilly, it will take some discipline and low gears to do the easier rides, but do try to do that. Have a fun ride! I'm sure you will.