I am from Pakistan and have valid visa USA b1/b2. In coming summers I am visiting USA along with my family. I have visited USA twice with my family .this time I want to visit Canada for 15/20 days and the. Proceed to USA by road entering from Niagara/Buffalo further to New York. We are four family family members:myself,wife,son 18yrs old and daughter 6yrs old. I need to know the procedure to adopted and easy course of action.
As a Pakistani national you will need to apply for a visa to visit Canada. The Canadian government website will give you the details.
You also need to be sure your US visa allows for multiple entry.
If you are already in the New York area, then crossing by road in the Niagara/Buffalo area gives you easy access to Southern Ontario. Arriving at the border with the appropriate visas and travel documents should get you in with no difficulty.