We had a great time staying for free at Rollins pass. We had a large group of bikers so we all hammock camped since there isn't much space for tents (lots of trees but not enough space to set up a tent). We were there for mtn biking and a show in Winter Park and it was an easy ride to and from town from the pass. There are lots of campers along the road since the top of the pass is the start of all the single track trails heading down into the town. 

I also stayed an extra night so I could leave early in the morning to hike James Peak and St. Mary's Glacier. It is easy access from here too. You will need to drive to the trailhead but it is less than a mile to the glacier and only a couple more miles to the peak. 

Even in Summer it is cold so be away and prepare yourself accordingly.