Below is a link that shows Green Lake on the map. You can see it's north of Madison, which he says he reached by riding his ebike. From Madison he went to Detroit, which is a much easier entry into Canada than heading north into rural Michigan.
At the time RB was entering Canada, nobody was looking for him to be doing that. He didn't have to sneak in through a border crossing in the wilderness, imo. And, his plan was to get out of North American quickly, not to survive in remote areas far from an airport. imo.
www.google.com