I have never done this, but if I am coming from Brussels through Toronto- onto the US (RDU) - the flight has 1 hr 40 min layover - do I have to go through customs/passport control/immigration and collect bags in Toronto and go back through security? Or is it just like a normal layover?

How much time should I plan as a minimum - FWIW I will have a four year old and 74 year old in tow - so running isn't an option.

Thanks!