Take a stroll around the park or rent bikes or paddle duck things
It is massive and overwhelming. You can make a day of the trip over there with a walk down Cherry Creek Trail or a jaunt around Confluence Park.
Free and great for all levels of activity.
You can go up to Red Rocks everyday before 3pm to see the amphitheatre with trails on premise.
Drive up a 14er, bring a jacket cause you'll need it!