It is about 490 miles, but would not necessarily be the fastest route due to the quality of roads.
the shortest air route is a great circle
The shortest route appears to be on W Tx 21 and W US 290, 80.2 miles
The shortest distance is via Fort Worth and Amarillo using Interstate 45 and US 287, however the fastest route uses Interstate 35 North and Interstate 70 West.
who am I
The route with the shortest driving time is about 360 miles.
It appears that the Shortest route I can find is from Jacksonville Beach, FL to San Diego, CA, at a distance of 2,109 miles according to Google Maps.
The shortest route between 2 points on the surface of a planet is a great circle route, which is a path that follows the circumference of a circle formed by the intersection of the planet's surface and a plane passing through its center. This route represents the shortest distance between the two points.
Great Circle Route
Take I-84 EAST to I-80 EAST to CHEYENNE in Utah.Take I-80 EAST to I-25 SOUTH to DENVER at EXIT 359A in Wyoming near Cheyenne.Take I-25 SOUTH to Denver.
Because that location is the lowest, shortest route between oceans.
straight line