If you are already in Bellingham go straight north to the Lynden/Aldergrove crossing then to 1, no need to go to Sumas. Take 5 north from Hope, 1 is closed at Spences Bridge due to the fires. Smoke may limit your scenery but once past Kamloops all is good.
Do you need full hookups? If so stay outside the parks as their services are limited to a picnic table and outhouse. Your furry companion will present no problems but he/she will need to be leashed. BTW, there is a really good Mexican restaurant in the strip mall at the north end of Lynden but don't order the large plate. Just sayin':B