The initial walk along the park and campground roads is scenic, with pine trees lining both sides of the road. The Birch Mountain Ledge Trail itself is a moderate forested hike that climbs a short bit and then runs along a ridge line before descending down to Sebec Lake. There are no sweeping views from the trail but it's a pleasant hike. A short trail connects from the lake to the campground road but I elected instead to explore the campground itself.
Here is a map of my seven mile hike.