took my boys (11 & 14) on their first metric century last Saturday. Cape Cod Rail Trail to keep it safe:
http://connect.garmin.com/activity/217678819
only a few miles it sank in that the younger one was outgrowing his 24" bike, so we hoisted the seat up and raised the handlebars so his knees were not bouncing up and down so much. the unfixable problem however was that the bike has a high gear of 14x32, which was the same as my third-lowest gear (!). the little guy kept spinning his heart out to keep up with us, though. at 40 miles he pulled over and almost quit, but somehow summoned the energy to ride 17 more miles back to the head of the trail.
we had started late, so by that time it was dark outside and the 11-year old was "done" after 57 miles. but the 14-year-old was determined to finish the full 62.14. it was dark by then (8pm) and I told him he couldn't do the trail anymore (though we had lights). so he did 25 laps around the parking lot to finish off the last 5 miles while I hung out with the little guy.
what a day! the older one is already talking about a century (and he would have no problem - would have finished in 4 hours if not for his younger brother needing to stop so often). but I'm even more impressed with the 11-year old, who I bet would have also finished in 4 hours on a better bike.
so where are safe places to do a century in and around Mass? we can always do two loops on the Cape Cod Rail Trail, though that's a bit boring...