This link in the King County Regional Trails system extends from the Sammamish River Trail just south of Woodinville eastwards to West Snoqualmie Valley Road near Duvall. A part of it also extends west from 145th (Rte 202) and Woodinville-Redmond Road towards Bothell; this section contains many road crossings including a road detour to cross over Hwy 405. After a road ride across the Snoqualmie Valley and north towards Duvall, the other end of the Pipeline Trail extends from Duvall Park east again to where it crosses NE Big Rock Road near 291st Avenue NE. The pipeline continues east past that point, as well, but is no longer park of the King County Park system beyond that point.
The trail can be quite steep in places, with the steepest part in the first mile and a half east of the Lake Sammamish Trail. In general, though, it is wide and well maintained. As the trail slices through suburban neighborhoods, there will be a lot of road crossings.
145th (Rte 202): Ballfield parking lot on the north side of NE 145th Street adjacent to the Sammamish River Trail has lots of space, but can get full on weekend days when many games are scheduled.
216th, Redmond: where 216th Ave NE crosses the Trail, there is parking room for a few rigs alongside the trail to the east.
Kathryn Taylor Equestrian Park: ample parking for many rigs off of 232nd Avenue NE, Redmond.
Open
Length: 13.7 miles
Surface: gravel
Share with: walkers, joggers, bicycles, dogs
Parking for: depends on parking
area, see directions above
The pipeline is owned by the City of Seattle, but the park is administered by King County Parks. Neither agency seems to have an official website for it, but if you do a web search you will find that many bicycling sites have detailed descriptions, and occasionally maps, of the trail.
Map: the trail is shown on the King County Regional Trails map:
Regional Trails map site