If you have...
...one hour or less:
Walk from Hovenweep Visitor Center to the near side of Little Ruin Canyon. Walk west on the path to Hovenweep Castle and Square Tower, 1 mile round trip. From a close vantage you can see many structures; from Tower Point you can see ruins located on the far side of the canyon.
...one to two hours:
Walk the Square Tower Group loop trail, 1.5 miles round trip. Hiking to Tower Point adds an additional 1/2 mile. The trail is a moderate hike through junipers, sage and cliffrose along the canyon rim. The trail descends 80 vertical feet then climbs to the same elevation when crossing from one canyon rim to the opposite side.
...a half day:
Walk the Square Tower Group loop trail. If you are driving a high clearance vehicle, ask a ranger at the visitor center about visiting the Monument's outlying sites. The Holly Unit features a petroglyph sun panel and amazing architecture. The Horseshoe and Hackberry Units have fine examples of "D-shaped" towers. The Cutthroat Castle Unit is situated among pinyon trees. The Cajon Unit overlooks Monument Valley 50 miles to the Southwest and is particularly beautiful at sunset.
...a full day:
Walk the Square Tower Group trail. Then, hike the Holly Trail 4 miles one way, starting at the campground. From Holly Ruins, walk north along the access road 1 mile to the Horseshoe and Hackberry Units. Hike the 1/2 mile trail to the ruin sites and return to the campground via the Holly Trail. This hike is approximately 12 miles round trip.