Dirtworks will have to wait a year. Haven't ridden for weeks, not likely to do much until I get a job closer to home.

FWIW, I did the 101 mile race with little more than a longest ride of 30 miles off road. Most of the training was on road, long rides and races. If you had a nice 10km dirt loop you could build it up to 10 times around over a series of months to prepare properly for it.