According to All Trails –
3.0 Miles
705 feet in elevation gain
OR
On our trip, we went around the other side of Hadlock Pond, to the private property that links up to Route 3, then we looped back. That was approximately 4.51 miles. You can see my recording here.
Dogs: I would bring a dog up here for sure.
Kids: If they are ok with the initial climb and distance, I think this would be an excellent hike for kids!