I assume riding bikes has something to do with your plans. Have you done your looking on TrailLink.com?
Within a 100 mile radius of Spokane are a number of great trails and many miles of riding...
Trail of the Coeur d'Alenes 74 miles - the best destination trail in the West.
Route of the Hiawatha, 16 - outstanding, tunnels, trestles
The Spokane River Centennail Trail, 39
The North Idaho Centennial Trail, 24
The Fish Lake Trail, 10
The Columbia Plateau Trail (N end) 24
If you are up the BC Okanogan - the Trestles of Myra