If you're looking at the Tri-Cities you should be OK for storing your trailer on your driveway.
I'm in Pitt Meadows and there is no bylaw against it.
Coquitlam has a maximum length allowed - 28ft I believe.
Port Coquitlam - not sure.
Port Moody - well, if you can afford to live there then storing off-property shouldn't be a concern
Have your realtor get the facts for you 'cause most storage "facilities" are out in the Fraser Valley area (Aldergrove/Abbotsford) and amount to a farmer's field.
Cheers, and welcome to the "Left Coast."
Mike....born and raised in the Vancouver area.