The Cowlitz River Trail follows its namesake river along dike on the east bank. The trail is asphalt and connects Kelso residents with the riverfront. The trail parallels the active BNSF line that carries Amtrak and much of the north-south freight in the Pacific Northwest. Access is limited to the trail because of grade separated crossings, but you can access at the endpoints or at Mill Street. The trail may be extended north in the future.
Parking and Trail Access
Looks like a great place to bike! I'll try it out some time.