Eric,
Follow the 12 week Weight loss and Base training plan. After that an 8-10 week cycle on a Build, Peak and Race plan will increase your top end and speed and put you in a great position to get more from your 100 miler PR plan this year.
Category 1 Cross Country Mountain Bike Build, Peak and Race Training Plan is my first recommendation for between your Weight loss and 100 miler plan
TIME CRUNCHED Category 1 Cross Country MTB Build, Peak and Race Plan will be a good alternative if you are time crunched.
Lynda