You might want to check the area out around Soap Lake, some impressive land formations in that area, also south of I-90 about 50 miles before Spokane is pretty interesting to photograph, around Grand Coulee is also nice, especially if you catch the right light, Dry Falls is a fantastic area to photograph as well.

The area I live in now, is right on the shore of the old Missoula lake, the lake actually filled several times and the dam broke over the 1000's of years, and was instrimental on helping to create the Columbia River gorge, which in itself is a fantastic place to photograph.

Have fun Mike, great stuff out there to shoot.