The Adirondack Park is both the largest and the first government-protected park in the contiguous United States. It covers a vast expanse—bigger than New Hampshire—of rugged, thickly wooded, mountainous terrain in northeast New York State. The Adirondacks are a popular destination for all lovers of outdoor activities, from hiking and skiing to ice and rock climbing.
The main route along the eastern edge of the Adirondacks is Interstate 87, commonly known as "the Northway." The Northway has beautiful views of the mountains, but limited services north of Lake George.
The main roads around the High Peaks region are Route 73 to the north and east which runs through Lake Placid, routes 3 and 30 through Tupper Lake to the west, and route 28N and Boreas road to the South. Gas stations are available about every 20 miles in these areas.
There is limited service by bus from Rochester, Syracuse and Albany to points north including Keene Valley, Lake Placid, Tupper Lake and Plattsburgh. This service is provided by "Trailways" bus service.
Amtrak's  aptly named Adirondack train runs between Montreal, Quebec and Penn Station in New York City with a stop in Ticonderoga plus other stops that connect with local shuttles to nearby destinations. The train leaves Montreal at 9:30AM daily, and New York at 8:30AM. The trip takes approximately 10 hours but expect delays at the border.
Adirondack Scenic Railroad  ride from Utica's Union Station to Thendara, just south of Old Forge, or depart on shorter excursions from Thendara to Big Moose Lake, Otter Lake or travel between Saranac Lake and Lake Placid, departing from either location.
Except for improved public campgrounds, there is no fee to camp or travel on state land.
There's so much to do in the Adirondacks... hiking, biking, camping, fishing, vacationing. Adirondack.net has a mountain guide for hiking. There is also the ADK club, which has lots of ideas on things to do.
Other things to do in the Adirondack Region include:
Get a tent, sleep almost anywhere.
There is very little crime in the Adirondacks. The most common problem is travelers going into the wilderness without proper experience or equipment. There is prevalent wildlife throughout the Adirondacks, and interactions between humans and wild animals is common.
In some areas, bear resistant canisters are required. Check the areas where you are staying to see if this is the case.