加拿大驾照 可开 as a visitor, however:

It is better to get a local 驾照.

In US, different states have different policy about 驾照,

for example:

In CA, you have to take the paper test and road test(if you passed the paper test) with your Ontario 驾照, even you have 驾照 in other states of US, you still have to take the paper test.

In CO, you did not need to take any test, just show your Ontario 驾照, and then they will give you a local 驾照.

So, different states in US, different policy about 驾照 of Canada.