This area can be a little busy on summer weekends, but it's worth the visit. The Brook Trail follows Tumbledown Brook up to Tumbledown Pond where you have fantastic views over the valley. From the pond its less than a mile to the summit of Tumbledown Mountain.
Park in the lot across the road from the trailhead. There is a restroom near the start of the run if you need it. The Brook Trail is possibly the easiest way up Tumbledown Mountain, but it's no joke. You'll enjoy the melodious sounds of Tumbledown Brook as you wind your way up the trail, which starts off mellow enough. However, it gradually gets steeper and eventually climbs in earnest, about 1.5 miles in as you ascend to the pond.
Tumbledown Pond is a popular rest stop and is hemmed in on three sides by rocky outcrops and trees. The views out over the valley are stunning though, especially in the autumn. Many folks actually turn back here.
From the pond join the Loop Trail heading west. You'll ascend a bit more, but the grade is nothing like the final climb on Brook Trail. Traverse the rocky outcrops and enjoy the views along this section. A quick trip on Tumbledown Mountain Trail takes you to the summit and even grander views.