Given the choice: comfort biking vs more running

Let me preface this with the fact that my anal retentative nature and training neuroses loom large.

I missed a ride this week, no biggie in the scheme of things, I know, but I have time tomorrow to get a workout in and would prefer to not have two days off this week. I'm only in week 9 of a 36 week IM Plan, so I'm aware that I could sleep in rather than choose either option here. But I'm going to do one of the other. As I am out of town, I have two choices:

1. I can rent a mountain bike and do some riding around DC or on the C&O for about 90 minutes. This allows my traveling companion to particpate in the biking and could even be a pleasant way to spend the AM prior to our somewhat stressful family visits (an entirely separate story!). Biking is my weakest of the three disciplines.

2. Go for a run on my own in the morning. Probably more cardio this way, but it is also companionless. In addition, I'm running the GWParkway 10 miler the next day. Running is also my best of the three disciplines and I've done all the workouts this week leading up to the race.

Which option would you choose?