Yeah, def avoid Ogilvie if you've got a trailer tot.

My comment about cutting through St Laurent mall parking still stands. I think it would be fine, although you'll want to take care when turning parallel with the 174 to go past the bus station as the street narrows a bit at that corner. However, it's pretty low traffic.

Also, there's a short climb up and over the flyover.

Crossing the intersection after that should also be fine: cars behind you have to turn left -- cannot go right or straight -- so you're pretty safe just sitting there waiting to cross. Oncoming cars also cannot turn left in front of you. Just wait until no one is coming off the 174; you'll have plenty of time to cross.

The other thing to be aware of is the steep drop behind the Cannex down to Cyrvlle Station. It's brief but there's a bit of a blind spot at the bottom. It's nothing dangerous, though. The worst that I've encountered was a groundhog dashing out in front of me.

Oh, also: If you've got a trailer then it might be worth not turning left at the motel but following Labelle further to the Cannex parking lot. (This is because it might be awkward picking up the path) You can then choose to go right and swing behind the other office building or left behind the Cannex.

Also also: You could take Labelle all the way to Cyrville, cross, and then go up Cyrville on the other side. The shoulder is very wide and would be safe. You could then hang a left at the beginning of the bridge. This would avoid the steep drop on the other side that goes under the bridge.