Wrentham State Forest is one place where it is legal to ride motorbikes, at least a certain times of the year. It's suprising to see there is some decent riding very close to down town Boston in fact only 30mins ride depending on traffic. The tracks I took were almost entirely single track. The tracks range from easy gravel with small whoops and berms all the way to rocks the size of my fist and steep sections with crumbling rock walls to negotiate. Usually people question me when they see me riding these trails on a big DR650 with street tires, but the trails are perfectly fine on larger dual sport bikes. ENjoy!