I think that might be what SharonNeedles was saying. CR, if he knew the local roads, could probably lead police there driving, but if he was trying to describe it during the interview, he wouldn't have known the road names to explain it. Thus he used a map. I think that part makes sense.
What doesn't make sense is how he would know exactly which route he took if he had blacked out. We know where he started, and we know where he ended, but there are several ways to get from point A to point B, and if he had blacked out, he would have been guessing on which one he took. Unless he had a map from that night.
I want so badly to disprove his "blocked memories" story!