The lines can be really long crossing back into the US by car at Blaine. I'd guess Sumas would be quicker. There's a really nice campground north of Sumas. It's called Golden Ears Provincial Park and the campground is on Lake Alouette. It's special to me because I took one of my first and most enjoyable bike tours there, back when I was a student in Bellingham in the mid-1070's. I would guess that it hasn't changed too much, but who knows. It was beautiful then! There's also a cool history site in Langley, B. C. - old Fort Langley, which had displays of what frontier life was like in old B. C.

I think there's a good bike trail on Vancouver Island between Victoria and Nanaimo. Do a search and you should find it easily.

A visit to the islands is almost mandatory. Their called the San Juans in Washington and the Gulf Islands in Canada. I think the best way to go to the San Juans is by bicycle - leave your car on the mainland. But then you'd either need camping gear or you'd have to stay in a motel/B&B/inn. The reason bikes are best is because the price of driving a car on the ferries is very high, plus there's often a long wait to get on a ferry - sometimes several hours to get back to the mainland on a weekend - while bikes ride to the front of the line and get on the next available boat. I've only visited the Gulf Islands via pleasure boat so I don't know much about traffic, ferries, etc. They're beautiful though.