Most of the ones that come to mind are far from here. Unfortunately, like you, I've found that maps aren't completely reliable in terms of what's paved and what isn't - also that it really sucks to drive to a ride you can't do. Sometimes roads on maps don't even exist (sometimes anymore). I like riding in good scenery and find a lot of places I bring my bike by also being a hiker. I'll drive to a trail, and want to come back and ride there too. 🙂 Sometimes you can find good info about road conditions on hiking sites because people want to know if their Prius will make it
If you're willing to make a weekend of it, Totes Coulee Road would make a fantastic climbing ride. Outside Tonasket. You can gain something like 6,500' over 30 miles? And not see anyone?
I'll second the Chewuch Roads. Falls Creek is paved to the end. It just burned, I don't know what it's like now. Again very low traffic.
Washington Pass from Mazama is great in a weekday until the afternoon. Cutthroat and the Overlook are good side trips.
Locally, I've heard Tiger Mountain is good.