Hard to give advise without more of a background.
Do you race your local XC events?
How many years have you been riding?
How much do you ride a year?
How long do you think it will take you to do the 101?
On the surface a 12 hour race/ride 2 weeks out might be too much for the average person. However, maybe you have done a bunch of these things before and its not a big deal.
Maybe goto the 12 hour race and ride for 5-7 hours and call it quits. Good training and not pushing the limits.
Do you race your local XC events?
How many years have you been riding?
How much do you ride a year?
How long do you think it will take you to do the 101?
On the surface a 12 hour race/ride 2 weeks out might be too much for the average person. However, maybe you have done a bunch of these things before and its not a big deal.
Maybe goto the 12 hour race and ride for 5-7 hours and call it quits. Good training and not pushing the limits.