a folding tourer might be the way to invest--- he's going to grow into a full size bike soon, and the versatility and commuter-utility and adjustability of a folder might be just the thing. It'll also give him an excuse to carry a little less weight.

I did my first MS 150 with my father at 12, and did another at 13. Great age for long distance riding! Looking forward to when my sons approach that age.