If you plan to stay in Canada, it's better to exchange your money to Canadian dollars. You need to exchange from USD to CAD in Canada anyway and the USD->CAD exchange rate is not good as well.
Bring cash and bank draft (i.e. not the traveller check). You need some cash for taxi, phone calls, hotels, and other immediate purchase. Usually, you can use the money immediately when you depost the bank draft to the banks in Canada.
When you meet the Canadian custom and immigration officers, you will show all your fund (i.e. money) to them as a family. i.e. You will fill in a single custom form for all your immediate family members. (It is different from travelling to China. i.e. 1 form per person)
