Going into Canada is a breeze, Canadian guards could almost care less. Coming back into the US is a different story... Make sure you don't have any produce or fruit. Best bet is to dump it before you get to the border. Last fall we had a half a melon and cut up head of lettuce and almost didn't get back in. The border officer was treating us like a couple criminals and wanted to search the coach... That was until some woman jump out the car next to us and tried made a dash to restroom. She didn't make it either way... The officer told me get on my way and don't ever try that again (it's going on my record).
What ever you do don't lie to them, it's felony.
