We do the crossing at least 50 times a year.
Successful method: Passport or Nexus card. No weapons, no record, no "sneaky ****", complete honesty with the officers, good attitute.
The officers will ask you some innocuous questions that may seem odd, but they're designed to detect lies and partial truths. They don't really care about your answer per se, but they care about the quality of your answer. Stick to the facts, don't stumble over your answers, be friendly, DO NOT express any frustration over the delay and enquiry, and everything will be fine.
If the officer asks, "Where are you headed in Canada?" Tell them CFR2009 in Nakusp, BC, or the Canadian FJR Rallye in Nakusp. Don't say something dumb like "Riding around."
When the officer asks, "Do you know these other motorcyclists behind you?", say "We know one another from the internet, the FJR Forum, and we're headed for a rallye in Nakusp." - Say something that sounds engaging, don't say something like "Yup!"
Tips:
Loosen your helmet strap while you're in line. Remove your helmet as you hand the officer your passport. A sticky note with your license plate number and state will help the officer (motorcycles are too short for the camera system, so the plate doesn't show on his screen). Answer the questions with a smile. Once cleared, slip your helmet back on and roll away. DO NOT STOP in any area that looks like an inspection zone. Just roll away slowly and fasten your helmet and gloves a little distance down the road (about 1.5 blocks).
ONE MOTORCYCLE AT A TIME. You can roll to the line two at a time, but you must see the guard one vehicle at a time. Pillions have to do the same helmet/paperwork thing that pilots do. (Show paperwork and a face to match.)
When you're asked if you're bringing anything into Canada, TELL THE TRUTH. - Say "Just personal effects." If you're bringing liquor in, say "Yes, my legally allowed X liters." (I think it's 2 liters but I don't import, so look it up yourself.) When you're asked if you have any weapons, you'd BETTER say "NO" and be telling the truth. CN weapon laws make CA laws look like the old west.