I think we'd only see that as a serious possibility after a conventional military invasion had turned into a quagmire, and we'd only see a conventional military invasion after a lot more provocations and failed "economic" annexation attempts.
I think Trump believes that Canada really is just some piece of real estate he can "acquire", but that very fact means that he's not going to go straight to the biggest guns because he assumes the Americans will be welcomed as liberators after just a little effort. It's only when those little efforts keep on failing that there'll be ramp-up.
This will take years. We're in for a long haul, and victory for Canada is possible at each step along the way, so I'm not too worried yet. Angry, but not worried.
Ideally, we'll help Ukraine finish off Russia in the near future and then we'll be able to purchase a ton of really spiffy gear from Ukraine that'll take an invasion off the table. Ironically, all that military hardware the Americans gave Ukraine under Biden can now be reverse-engineered to make good anti-American-forces drones if needed.