Prospect, TN
Albany, NY
Grays Corner, ME.
Brunswick, GA
Melbourne, FL
Brunswick, GA
East Brunswick, NJ
Brunswick, Georgia would be the Halfway point, but many would choose Savannah, Georgia an hour and a half north of Brunswick for the amenities.
There are two Prospect Parks. Bristol, PA is halfway for one of them. Bloomsburg, PA is halfway for the other.
Travelling down Interstate 95 the halfway point would be the Jacksonville Florida area.
The half way point between St.Louis to Ft.Walton Beach would be Huntsville AL. This is a 26 hours and 28 minutes drive.
The halfway point between 5700 and 5800 is (5700 + 5800) ÷ 2 = 5750