I'm sure "resistance" meant the French Resistance, "the boarder guards are not expensive" meant the border guards could be bribed for a reasonable price. If you were near anyone demonstrating and the Vichy Government army (friendly to Hitler) was approaching, you would want to run because you would be shot with the demonstrators. Checkpoints at the highways  would mean they were guarding the borders or looking for someone in particular so you better have some good ID or better yet, sneak across the border where they weren't watching so closely. Through the mountains, most likely. As some of you may recall, construction workers in England (and elsewhere, I'm sure) are still finding undetonated bombs from the Blitzkrieg and WWII all these years later. Interesting book. Most likely a collectors' item.