I have OCed in the Post Falls Cabelas, restaurants, gas stations etc all over Idaho many times without a single incident. If you have time try the White House Grill in Post Falls for lunch or dinner, my wife makes me drive the 40+ miles each way just to have lunch there. Yes Idaho honors Washington CPLs, however Washington does not honor Idaho permits. With a WA CPL I cant think of a way you could be unlawful in a car outside of waving it at other moterists or something equally silly. I have never had even a comment about my firearm in Idaho and I OC every where I go. IANAL just so you know.