Hate to be embarrassed at border

Tubaronnie wrote:
Heading back into Canada-1st time with motorhome. Entry/exit @Port Huron/Sarnia. What lanes do motorhomes use coming/going?.............

Sarnia? - you will use the regular car lanes for sure. That's the left lane as you head over the bridge towards the booths.
The middle lane is for Nexus/Fastpass holders and the right lane is for trucks.
Watch for the red/green light over each booth to see the ones that are open.
Go slow and use the lane width guides as you will be quite wide, especially the mirrors.
BTDT :)
Good luck