You'll need a commercial drivers license. Also you are subjected to SCDOT. They came around the buses a few times and I got pulled once while DRIVING A CITY BUS. It is a bad time and if they find something wrong with the vehicle, its an even worse time. I was on the side of the road for 50 minutes. Fortunately I was on campus so I just had another bus on the route come get my passengers.
Oh and CDL license test sucks. But everything...LITERALLY EVERYTHING on your vehicle has to be in top notch condition. No worn bushings. Crappy shocks, bald tires, bad bearings, nada.
The extra $$$ isn't worth dealing with that headache.
As for being an actual hot shot, you gotta be flexible to be successful. And also plan on being empty on the way home. We used hot shots at my old job, taking emission control equipment to Portland, OR and whatnot. It was rough because often the truck would break down and we had to get a second one. Oh and I've never seen a hot shot truck that wasn't beaten to crap.
If you want a side job, become an HVAC guy. There is always someone on the weekends or evenings that needs freon in their AC. Go buy an old minivan or SUV for cheap and then take it whenever you need to go do work. I just paid some guy a lot of effing money to basically do that. After watching him, I hope my next house will have the new freon in it and I can just recharge it myself (barring leaks). You gotta go get some certificates but judging from the guy who did mine, obtaining said certificates shouldn't be that difficult.
Or buy and sell cars. Like my friends effing Jetta. Buy it, fix the oil-to-coolant leak and misfire. Clean it up, replace all the broken interior parts, sell it for +$2k. Done. You can always sell Hondas and chevy trucks. Those always move. Go do whatever to get into auctions and then use your truck and trailer to bring it home. Get a google number so when the SOB runs it into a tree and demands a refund, you can ignore them.
Or car parts. Here in ATL, I discovered a lucrative market in sedan parts. Who would've known. Oh and Land Rover Defender parts. People love them some wheels, bumpers, and doors.
Dunno, just trying to offer some other side cash ideas that don't involve misery.