We traveled from Lincoln NE to Chilliwack during June 2016 to pick up our 21'. If you have pets, I suggest looking for La Quinta Inns as they are very pet friendly. The nite before orientation we stayed at the La Quinta in Bellingham WA. Orientation day consisted of dropping our dogs at Lynden Vet Hospital where they spend the day. Nice people, they also let us keep a cooler of food there so we wouldn't have to hassle with the food or dogs at the border crossing. Orientation, then back to KOA at Lynden. Get a pull thru site. We made the mistake of getting a grass site by the lake..... tracked in grass like crazy.
Another tip to beat Seattle traffic ... come down thru Fidalgo Island to Fort Casey (Deception Point Park is super nice). Take the ferry across to Port Townsend. Then drive down just east of Olympic National Park (we did not have the time to stop, but want to get back there someday). We camped on the coast and Cape Disappointment WA and Nahalem Bay OR before heading back east. If you go this route, be sure to stop at Canon Beach OR. Stopped at Deschutes River State Recreation Area OR and Three Island Crossing State Park ID. Last night before home was a Walmart in Cheyenne WY
.... Hope this helps.