Crossing Over — Paul Clayton

The chaos and violence of the second American civil war arrives in Mike McNerney's town when knife-wielding thugs invade his home. He, his wife, and their disabled daughter, take to their camper to find refuge in Canada. Along the way they evade roving criminal gangs and warring militias. They finally reach the border only to find a large encampment of others, desperate to cross over to safety. With their money almost gone, an unscrupulous immigration official offers to usher them through … but will they pay his obscene price?