My weekly average is 35 miles.
Biking is unpossible on the days I work (I have a fairly physical job, lifting and carrying, walking), and I usually get 5-10 miles in on my days off, depending on the weather. Days I work, I'll bike to and from the train station--4 miles/day.
I've signed up for a different race that doesn't require that I raise $200. And it's not until August, so I have an extra month to get ready. It has a 20, 30 or 63 mile option. I can definitely do the 20 mile (if barely), but I think I'll shoot for the 30 mile race. It's a fundraising race to help pay for parks, which isn't as great a cause as fighting diabetes, maybe, but I really don't imagine that I'd be able to raise $200. I don't know enough people who have money.