I live in Stow and have ridden most of the conservation lands. Rattlesnake is a nice change of pace as fvh420 says, definitely more technical than STF. I like to take my HT on the tour de Stow, starting from ~the Stow Community Park to Delaney through Marble hill, Heath Hen, Flagg Hill, Captain Sargent, Red Acre, Stow Town forest. A little road riding is necessary. You can also venture into Boxborough, Acton, Bolton, Harvard, Sudbury and Maynard pretty easily to add miles on. I can send the URLs to some Garmin track if you are interested.