Just got back from a great short holiday up north but there are a couple of trouble spots to be aware of if you heading to Montreal via US Route 91 and Canadian route 55.
First, at the border there is construction going on the US side. Everything converges into one lane before the trucks and buses go into different lanes. It can take a while to go through.
Second, after you hit Canadian route 55 which takes you to Route 10 and Montreal beware that the exit heading west onto 10 is closed for construction. There are detour signs but they are small. You head east on 10 for a mile or so before turning around. Don't rely on your navigation system. I know my way around but we were using it as we were going to get off later in Bromont for the night. The navigation system had me do a complete circle back onto 55 and the closed exit. Fortunately the second time around I saw the small detour signs which I eventually followed.
Bottom line, if you can come north via US Route 89 do it!!.