Yü W.
Google
The 0.6-mile riverwalk is a short, well paved path between Riverside Dr and Flower St. You could continue east after Flower St but there is no outlet beyond that point. Great for walking, running, biking with a nice view of the LA river. The little park near Riverside Dr is also cute.
The better version would be the bike path across the river, you can take it for 7 plus miles all the way to Lincoln/Cypress.