He really got the understanding of a map, (finally) when we were at Disneyland last year. As all the rides are laid out on it. We would pick a ride, then he would orient the map based on where we were and he'd follow the rides on the map with what he say in front of him. Worked really well.

Maybe a county or state fair near you, (or a theme park) would be a good really fun diversion to get him to understand ready a map and orienting himself to it.