The North Country has two interstate highways: Interstate 81 and Interstate 87, both running north-south. The former cuts through the region's western edge, while the latter runs near its eastern edge. There are no major east-west highways, although the Interstate 90 tollway (the New York State Thruway) traverses the state not far from the region's southern rim and connects Syracuse and Albany to the arteries that lead northward. From Syracuse, travelers going to Thousand Islands can catch Interstate 81, and follow it north.
To get to the Adirondacks Park from Syracuse, drive east to Utica, then catch Route 8/12 north to access roads going east or northeast: Routes 365, 8, or 28. Those traveling to the park from Albany can hop on Interstate 87 (not a toll at this point) which goes north through the park. From Montreal to the park, head south on Autoroute Métropolitaine 15 and be sure to bring your U.S. passport in order to cross the border. To get from the Thousand Islands into Adirondack Park, take Route 3 east out of Watertown.
Because the North Country gets considerable snowfall in winter, you should prep your car in cold-weather months. Distances between settlements with lodging and services can be substantial; stretches of 30 mi or more are common, especially in the central and far-north Adirondacks, so keep an eye on the gas gauge.
Some rules of thumb for when the temperature dips below freezing: keep your gas tank full (the tank can freeze if it's nearly empty); shut down all accessories before turning the car off (batteries only operate at 50% capacity when temperatures are at 0°F) and put some winter-mix windshield fluid in your wiper reservoir. You can find these mixes at gas stations throughout the region. You should be fine with all-weather tires.