i used to live a half of a mile from this trail. its mostly just flat paved trail. perfect for biking and longboarding. however, construction for the gathering place has closed it down from 21st to around 41st.
Took an easy ride along the water on a Sunday afternoon. There were a decent amount of people, but no one was in anyone's way. It's a fairly long paved trail. You can spend a good amount of time riding.