The Pittsfield State Forest is loaded with trails, most of which climb to the top of the mountain where they meet the Taconic Skyline Trail and are steep and rocky. Most trails are lightly used and you normally won't see very many people on them. This is ideal if you want to walk your dog off-leash.
Before you get started, let me warn you... very few of the trails are marked. This isn't the Appalachian Trail where there is a sign at almost every trail intersection telling you how many miles it is to the next trail intersection.
There is a 5 mile long paved road loop running up to the top of the mountain and back down which is popular with walkers, cyclists and cross country skiers.
In the winter, many of the trails and the paved road loop are groomed by the local snowmobile club and are fabulous for cross country skiing. Several other trails are ungroomed and are wonderful for snowshoeing.
In the summer, many of the trails are heavily used by 4-wheelers so tend to be quite worn down and rocky. Some trails are off-limits to 4-wheelers and are in better shape. The mountain biking is tough (lots of climbing), but well worth it.