Not sure about your intended route, however we have always found the border crossing experience at Port Huron to be far easier than at Detroit. We travel South to Texas every winter and have yet to have an issue with US customs at Port Huron. Anytime we have entered at Detroit we have always been searched and have found the staff there to be very rude. Traveling back to Canada we have had no issues with Canada customs at Detroit. So we always go South through Port Huron and back North in the spring at Detroit. Detroit has good duty free and cheap diesel coming back home. Your experience may differ, but this has worked for us over the past 4 years.