The snake that Daniel Boone calls "a coral snake" is not a coral snake, it is a rat snake.
When Daniel, Mingo and the Camerons part company the first time, Daniel tells him that if they travel down the road they should reach New Orleans in about 3 days. The current distance traveling along modern Interstate 10 between Lake City, FL and New Oreleans is 488 miles. The average speed of a wagon was approximately 15 miles per day, meaning it wore likely take 3-4 weeks to traverse the swamps and bayous.