Having lived very close to the border, sneaking across isn't that hard. There are tons of places where you can just walk across without any problems but don't do it often cause if you get caught, they come down pretty hard on you. More than likely, coming into Canada, you won't get caught as Canada isn't so worried about people crossing as the Americans. Its the US Custom agents that you have to watch out for. As for living in the woods, unless you are as resourceful as Richard Proenneke who built that log cabin in Twin Lakes Alaska, (you have to watch PBS to know who he is) I think you'll probably be dead within months.