I've crossed the border many times and have had the gamut of experiences from good to bad, nice border guard to surly. And that's for both US and Canadian officials. Sometimes border guards at rural less-trafficked crossings tend to be real nice, and sometimes they're real jerks. There doesn't seem to be any "rule" that if you go with a "smaller" crossing you'll get better service, or vise versa. And this goes for crossing on bike, in a car, or on a train/bus.
My bit of advice (other than seconding mdxix re: green food) is have your itinerary through Canada formulated in your head before you get to the border crossing. From what I gathered through travelling 'cross the border is that Canadian Customs/Immigration is most worried about you coming into the country, staying indefinitely, and mooching off of their social services. They want to hear that you'll be in Canada for x days, and only x days. So be ready to answer how long you'll be in the country and where you plan to exit back into the US. I know things can change a little, but having an itinerary you can rattle off makes them feel more confident about you being in their country. If you are flying or taking the train out of the country, it's good to have a printed itinerary or ticket to show them (if they ask.)
Also: don't make them suspicious that you'll be looking for work in Canada. If you say that you are unemployed or "freelance" anything you may face resistance.
You will definitely need a passport or passport card to enter into Canada and to return into the US. The passport card is a drivers license sized card that can serve as passport while travelling by land or water to other North American countries. And it's a lot cheaper than a regular passport. But it is only good for surface transport to a country like Canada, so if you had plans to fly out of Canada at the end, you'll need a regular passport.