This trail runs pretty much straight from Bothell to Redmond along the Sammamish waterway. Just before the bridge in Bothell there is a connection to the Juanita Hill bypass . At I-405 there is a connection to the UW-Bothell campus which is a start to routes north . There is a park with restrooms and benches at NE 175th called Wilmot Gateway Park. In Redmond there is a branch trail into the Redmond Town Center Mall. There is also a connection to the SR 520 trail . The Sammamish River trail ends in Marymore park. You can ride through the park and pick up the East Lake Sammamish trail to Issaquah. This trail is currently unpaved.
Here is the sammamish river page from the king county web site.
Here is a story about trail improvements on the Sammamish River trail