There is no lodging inside Canyonlands. Instead, you need to look to the surrounding communities.
For most park visitors, Moab is the gateway town to Canyonlands. But then, the park's four districts -- Island in the Sky, Needles, and the Maze, as well as the Horseshoe Canyon Unit -- are far apart when it comes to their entrances. As a result, you need to be strategic when you decide where you want to end the day.
Moab is good choice for many, as it's close to the Island in the Sky District with its lofty views down into the park, its short hikes, and its compelling geology. Plus, it's the gateway town to Arches National Park, and it has more lodging options than any other community close to Canyonlands.
Lodging options can be found on the Moab Travel Council website
Monticello, though decidedly smaller than Moab and with fewer lodging options, might be a wise choice if your interest in Canyonlands lies only in the Needles District. It lies just 14 miles south of Utah 211, which runs 34 miles to the Needles Visitor Center. Moab lies 70 miles away. Plus, Monticello also is closer to Mesa Verde National Park (tk miles), Hovenweep National Monument (tk miles), and Natural Bridges National Monument (tk miles) than Moab.
A list of lodging possibilities in Monticello can be found here.
Green River might be a good choice if you're only planning to visit either the Horseshoe Canyon Unit or the Maze District. The town, located along Interstate 70 north of the park, is 24 miles via Utah 24 to the turnoff for both destinations. Though from that turnoff you have a bumpy dirt road to follow either 46 miles to the Hans Flat ranger station (and a good clearance four-wheel drive is essential; no rental sedans recommended) or 30 miles to the rim of Horseshoe Canyon.
A list of lodging possibilities in Green River can be found here.