The trail was later extended west through Seattle's Fremont neighborhood to Eighth Avenue NW, and now it also reaches east to Redmond by means of the Samammish River Trail. I biked 27 miles roundtrip on the trail and thoroughly enjoyed the ride as I followed Lake Union, Fremont Canal, and Lake Washington, traversed the University of Washington campus, passed through parks and various residential and commercial areas, and enjoyed good views to numerous sights. A map is available here.
I parked at Gas Works Park, and after looking at the old machinery and piping, rode both directions on the trail which is a mostly level, wide, asphalt path, in good condition except for occasional heaves/buckles in the pavement. Some sections were very busy with walkers, joggers, and bikers, especially the section through the university campus.