As a stop over to Vancouver, we find ourselves in Grand Coulee, Washington. We've spent the last couple of months in, around and over the mountains from Taos to Calgary. Now, how to finish this western trip? I would like to go through the North Cascades National Park but Highway 20 has me concerned. Anyone here been on the Highway 20 route? I haven't read any motorhome warnings and thought someone here might have been there. Thanks.