Hadley Mountain is very popular for many reasons. Not only is the summit open with good views to the east, south (including the Great Sacandaga Lake), and west, but it also has a restored fire tower which allows great views in all directions. The trail is never very steep and is in generally good condition. During the summer there may be a summit steward to greet you and answer your questions.
The trailhead has good parking for more than dozen cars. It is reached by finding your way to Lake Luzerne (NY route 9N), then crossing the Hudson to the village of Hadley. Turn north onto Saratoga Route 1 for about 3 miles to Hadley Hill Road, turn left and go uphill for 4.6 miles to Tower Road (small sign on the left). Tower Road is an excellent dirt/gravel road that is often plowed and sanded in the winter. It leads to the obvious trailhead parking lot.