Need NAFTA job offer help! Leon, PMM, anyone!

Is there anyone who knows what Canadian immigration officers will be scrutinizing in a NAFTA visa application? I have been offered a job with the city of Toronto as an "Urban Fellow". The position is for 1 year, and selects many urban planners (although not exclusively urban planners). The duties include several activities that urban planners are hired for, although I don't know if it is exclusively ( could be consulting, researching etc.). I have my actual Master's diploma as well as my actual AICP certificate for credentials. What do I need to bring to the immigration officer and do I need to go to a POE or could I just go to the American consulate in Toronto? I want to show up with a crisp file to hand over and be as straightforward for them as possible. I need your advice desperately. My sincere thanks.