Re: central WA
I think the part where the forest service says "it's ok to shoot, but if you start a fire [intentionally or not] you're responsible" is enough to scare me back into the desert for shooting.
FWIW - I know of a crappy desert area that's open to the public, but even though it is fenced off and marked "no motorized vehicles", the dirt bike riders take it over and use the shooting berms for ramps.
Otherwise, it's a 200 yard walk from the parking area, and another 600 yard walk to the longest range (safe) shooting berm. It is in central Washington state. About 2 1/2 to 3 hours driving distance from Spokane as well as Seattle.
Otherwise, I think the Wenatchee range has the best to offer yet.