When I got my CDL permit packet, many moons ago, I received a list of Testing facilities from the DMV, as well as places where I could rent a truck. There was then a couple local companies who trained their own dump truck drivers, etc, and they would allow you to rent their truck, and use their training area. They did not provide an instructor or anything. I learned by a friend of mine being very patient, and reading the CDL Book over and over. Driving down the road is the easy part. One of the best things I had going, was my friend, who let me study his truck and I spent hours in a closed department store parking lot, practicing backing into their dock. I got so familiar with his truck, that he ended up hiring me to drive it.. my first expediting experience, 1993, Roberts Express, D1115, a cabover extended cab Mitsubishi, which a lot of people drove back then. Now it's rare to see a cabover straight truck.
You might check your local Department of Motor Vehicles, to see if they have such a list availible. Also, a truck driving school in Columbus, Roadmaster, is one of the testing facilities. They also had a Straight Truck with Airbrakes availible to rent. You would still need a licensed driver to go with you to be allowed to take the truck on the road. Could get pretty expensive, but if you could learn the basics of handling a truck by using a U-Haul or something, then in a short while you could transfer that, and learn the specifics of an air-brake system.
I'm sure Kentucky has something similar, first place to start would be you local DMV, or call truck driving schools.
Dreamer