The U.S. Forest Service has opened an experience that only comes around every so often in Colorado.

As weather allows every Saturday through June 15, the agency is offering guided auto tours to Picket Wire Canyonlands on the state's southeast Comanche National Grasslands, outside La Junta. That's the remote, rugged tract home to a long series of dinosaur tracks and many other intrigues of the deep past.

Reservations late this month opened at Recreation.gov, which bills the tour as a "unique and unforgettable family experience." Along with hiking beside the dinosaur tracks, guides show the way to Native American rock art and remnants of Spanish explorers and homesteaders.

Spots are $20 for adults and $7.50 for youth (ages 6-12). Those were selling fast at last check.

Recreation.gov offers a checklist of requirements. Visitors must drive their own four-wheel, high-clearance vehicles from the starting point at the Comanche National Grasslands' La Junta office. Also required is a spare tire; the rocky road into the site is notorious. And visitors are advised to bring their own lunch, water, snacks, proper shoes and sunscreen for the eight-hour venture.

The seasonal tours are the only authorized ways for vehicles to reach Picket Wire Canyonlands. Otherwise hikers, bikers and equestrians embark on a round trip spanning more than 11 miles from Withers Canyon trailhead.

A Forest Service webpage details that trip: tinyurl.com/43waezd4