When you make a reservation, check off the government/military rate. Its usually a really good deal and you should have no problems getting reimbursed provided you stay at Holiday Inn or equivalent hotels.. If possible pay by credit card and your bill will have the exchange rate on it which is also claimable.
However, if you are travelling through te US, you still only get the Canadian meal, TD, and mileage rates. The good news is that most prices will be cheaper so in the long run you win out.