I stand corrected. Apparently, you can export track data from a number of different Garmin GPSs, not only the Zumo.

I've been able to plug my Garmin Nuvi 1490 into the laptop running Win7 and it recognized it as a USB drive from which I can pull GPX files. Unfortunately, they seem to be in a slightly different format than the ones Yun Lung Yang provided from his Zumo. No biggie. It's slowly coming together.