Don't follow those instructions MGAlantine.
Do this:
Take the 401 east to the On/Qc border.
It becomes Highway 20 (du Souvenir) in Quebec: Stay on it.
About 25 Km into Qc, you will come to a major branch. One will offer you Highway 20 -Downtown Montreal: Do not repeat not take it.
Instead, take the Highway 540 branch out to Highway 40 East Montreal (a few Kms North).
Once on the Island of Montreal, take the exit for Highway 13 South (Sud).
Take that Highway to its end and stick to the left lane. It will put you on Highway 20 East again.
Then next take the exit for Highway 15 Sud / Pont Champlain.
As you exit the bridge - stay on that highway: It is highway 10.
About 15 Km later, take the exit for Highway 35 Sud - to US 89.
About 7 Kms later, take the exit for Boulevard Pierre-Caisse (it is right after you pass the big RONA store on your right).
At the exit: Continue straight on what is Omer-Marcil road (you will pass in front of the Walmart - eh!, now you know where the wall mart is: Bonus) until you come to a T-intersection. Turn left on that road: It is Grand-Bernier Nord.
Just stay on it until you come to the base's main gate on your left.
Good driving.