It may go smoothly. However, it may not. Hope for the best, prepare for the worst should be the motto. Set aside 2 hours extra. I live 20 minutes away from the US border in Canada. When I drive back into Canada, CBSA agents are really aggressive. They challenge and argue over everything I say for which I have no documentary proof. Two to three CBSA agents would throw questions at me together and then disagree with the answers that I give to them. Sometimes they would play good cop, bad cop to confuse me. After the questioning, full body is searched and everything inside the car is searched. If I had gone to play a cricket match then they will ask about everyone I met, what I did exactly with exact time it took to do each thing, where I ate, where I filled up gas, and so on. Will ask about drugs, weapons, and anything else that comes to their mind. Phones will be checked, and if more than one person is traveling then each one is questioned separately.
There is a lot of gang related activity where I live and several high profile target killings have taken place recently. Throw some drugs and human trafficking into the mix as well to understand the behavior better. Last but not the least, Canada is a junior partner of US and doesn't want Canada's problems to spill over into the US and risk border restrictions.