RBC and TD also allow you to open true USD bank accounts (located in the US) without having to set foot in the US.
Both allow transfers from your Canadian USD bank account to you US USD bank account, although RBC transfers can be done entirely online without calling in. TD’s checking account on the US side has no fees with a min balance of $100 and RBC charges about $4 USD a month for their checking account.
For the TD account any time you are transferring funds from the US TDBank USD Account to the Canadian TD Bank USD Account there is charge for the wire but it is reversed within 48 hours. And then end of the month we are charged about 1 USD for each transfer done in the month from the US to Canada.