LAVH Train for breast cancer walk???

Hi girls, had my procedure 12/16 and so far so good except for exhaustion. No pain,no bleeding, no meds, and resting. This coming may I'm suppose to do the Avon walk for breast cancer, which is 39.3 miles over 2 days. The training should start in the next few weeks, do you think it's possible??? It's drawn out over 16 weeks and combines mostly walking with light strength training. I could do the 12 week training but that is harder so I want to start Jan 17 if possible. I don't have my next post op appt til jan 27...