Campsites are available at the 80-site Grass Point State Park (Rte. 12 E, 315/686-4472) and the 429-site Wellesley Island State Park [1] (Wellesley Island, 315/482-2722). For reservations, call 800/456-CAMP.
Capt. Thomson’s (1 James St., 315/482-9961, www.captthomsons.com [2], $79–139 d) contains 68 standard rooms, some equipped with balconies overlooking the river. Hart House Inn Bed and Breakfast (21979 Club Rd., 315/482-5683, $95–255) served as the 1000 Island Golf Club and now offers peaceful guest rooms with fireplaces, whirlpools, and canopy beds along with a hearty local breakfast.
Featuring views of the river and Boldt Castle [3] is the luxurious 
Riveredge Resort Hotel (17 Holland St., 315/482-9917, www.riveredge.com [4], $160–325 d). The hotel’s rooms and suites are spacious and well-appointed; on-site are a health spa, indoor and outdoor pools, and two good restaurants.
The sleek Bonnie Castle (Holland St., 315/482-4511 or 800/955-4511, www.bonniecastle.com [5], $180–290 d) is the region’s largest resort, equipped with 128 rooms and suites, a conference center, private beach, swimming pools, tennis courts, nightclub, miniature golf courses, and restaurants.
Links:
[1] http://www.moon.com/destinations/new-york-state/the-adirondacks/the-thousand-islands/alexandria-bay/wellesley-island-state-park
[2] http://www.captthomsons.com
[3] http://www.moon.com/destinations/new-york-state/the-adirondacks/the-thousand-islands/alexandria-bay/boldt-castle
[4] http://www.riveredge.com
[5] http://www.bonniecastle.com