There is a barber who has a shop in the Petro truck stop in Spokane, Washington and he seems always busy. He has cut my hair and did a good job. His secret is low prices, low enough to get noticed by drivers who can easily wait a day and get a haircut someplace else.
He told me about increasing numbers of locals that come to him, including every boy in the 5th grade. It seems they all decided it was cool to go to a truck stop to get their hair cut. This particular truck stop is very nice. It is kept clean, has a nice restaurant, and has pleasant seating areas where parents can wait while their kids are in the barber chair. If they do not do so already, I can see it happening that his prices will motivate parents to get their hair cuts there too and maybe even pile a group of parents and kids in a car to go together to the truck stop for haircuts. I would guess he is the lowest priced haircut within a hundred miles.
It is very easy for a trucker to get a haircut at Wal-Mart since truck parking is usually available. I would not set my price for a haircut higher than Wal-Mart does. To attract driver attention, a dollar or more lower might be wise. The Petro guy has a sign out with his prices for short cuts and long cuts. Sorry, I do not remember the prices.
You could probably reach him by phone by contacting the truck stop.
Many truck stops sell a little book called the Pocket Truck Stop Guide. It will list all truck stops in Kentucky and tell you which ones are the largest. I would focus only on the large truck stops as they will have the most traffic. To attract local traffic as well, being located near a city would be a plus.