When Roger drops Andy off after fishing, Roger parks directly in front of the courthouse. Andy then goes inside and finds Barney taking a nap. A minute later, they go outside and the squad car is now parked in front of the courthouse. It hadn't been there a minute earlier, when Andy was dropped off.
When Andy and Roger Courtney discuss Andy visiting the Esquire Club, several references are made to "making it up to the state capital". If, in fact, the fictional Mayberry is actually Mount Airy, North Carolina, then the state capital, Raleigh, would be *down* from Mayberry, approximately 139 miles to the southeast.