Just brief information regarding how to win the challenge (at least some weekly Head to Head). I just found out

Each team gets matched against one other team, following the schedule (that's already posted in the tab above!).  When the results are in, teams get points for how they do in comparison to the other team they're matched up against that week.

1. Most miles logged: 10 points
2. Highest percentage of members posting at or above needed miles per week: 2 points
3. Most race miles logged: 1 point
4. Team member wins 1st place individual award: 1 point

ad 2, quoted from forum)

"Say your goal for the year is 104 miles =>2 miles per week.   But the first week, you have a surge of energy and run 53 miles.  So you need only 51 miles for the remaining 51 weeks.  Your revised goal goes down to 1 mile per week."

The "Goal" widget on the "Training Log" page is showing the current miles needed. It is changed dynamicaly based on kilometers/miles alread run, it is not simple number for every week like "1500 / 52 = 28,846".

I think I may be a little slow on the uptake in terms of goals. I'm pretty sure I'll be going over on my goal mileage this year. I purposefully underestimated because I have some pretty big stuff happening this year and I didn't want to let the team down. If I go over on my mileage, is that a problem?

Not at all - unless it's by a ridiculous amount (say double or more) and even then not really.  If one or two teams have most of their members greatly exceeding their goals it's possible the admins will break the team up, but that's rare.

Don't worry - run what you can, what fits your training and your life.