The CBP brochure:
https://www.cbp.gov/travel/us-citize...-before-you-go. I would consider the crossing at the Peace Arch a little tight for rigs. Consider the truck crossing Sumas a mile East of I-5. Going into Canada is usually the 20 questions of how long, where and weapons. Stay outside of Vancouver and drive in to sight see as the roads are very congested and hard to get around. Everything is metric and camera speed traps are everywhere. I've received a few in the mail and didn't know it. They have reciprical agreements with the US for license plate info and will use a collection agency to collect on a ticket at least once upon a time.
The Return is usually more intense getting back and the Officers conduct a 3 hat inspection at the border. 1st is to determine status,
Passport, 2nd conduct Customs declaration and animal health questions and 3rd is to look for Agriculture concerns. The Agriculture aspect can be a hit and miss sometimes depending on the experience of the officer. Bananas should be OK, but the next one determines them as a prohibited item, cooked meets; No- problem, but some confiscate them. The real agriculture specialist work's the inspection areas. Just be ready to declare all fruits, vegetables, meats and plants and everything should go pretty good. The failure to declare is all they need and they can present a $500 fine, which plagues you indefinitely crossing the borders. I tried to find a descent campgrounds in and around the south area, but no recommendations. Within 5 miles of crossing into Canada is the US possession called Point Roberts, WA, maybe a state park is there. You have to cross the tiny border every time you go out.