Do check maps, routes and trails ahead of time.
Do carry a compass and GPS when heading out hiking or biking.
Do drink tons of water to battle the altitude.
Do expect to hit traffic especially on Interstate 70 if you're headed to the mountains to ski.
Don't get stuck on a road that's burlier than your car. Heed signage.
Don't forget winter gear such as snow chains, warm clothing and an emergency kit.
Don't start a summer hike late. Afternoon thunderstorms roll in quickly.
Don't depend on cell-phone service in the higher elevations.
Don't laugh off "Falling Rock" signs; rocks really do fall out here. A lot.
Matthew Schniper and Kirk Woundy