For a sole proprietor business there isn't any real benefit to forming an LLC or C corp until your profits get near 100k a year according to a trucking radio host I listen to. And the only reason is for income tax. Your assets won't be protected because you are both the owner and the driver. Despite what JDoremire said, I've enjoyed transporting trailers. It's a part time job that I work at my convenience. By leasing to a transport company there are no fixed costs like insurance, drug testing co-ops, and all the other expenses that are required by the FMCSA. The company I lease to pays all those expenses and also tolls, permits, and other ancillary costs. Income exceeds expenses by an acceptable margin for me, but mainly because I can do my own repairs and the 12 valve is so reliable. I estimate the job has paid for my truck about 7 times in the last 12 years in profits, but mainly I drive because I like to. Regardless of what you drive an owner/operator needs to know the fundamentals of business and be willing to provide a service. It isn't just starting the engine and pulling a load of stuff from point A to point B.
I and others would love some deep insight as to how things work out to be profitable. It would save some of the newbies a small fortune. I didn't say it wasn't enjoyable. However there is a bunch of paperwork involved that isn't fun or "just driving". The linked 2007 thread the member brods posted is still true about deadhead and other work like hot shot and hauling cars being more profitable.
Some of my insight into it... Today you can't show up with a antique 12 valve and expect to be put to work hauling RV's. No.... They (the major RV brokers) want you to show up with a late model 5 years old or less pickup that requires a ~$700 a month payment. We started in 2008, had one good paycheck, and the Great Depression V2.0 hit. Diesel hit $5.00 a gal. None of the factory to dealer work was available. We wound up hauling closed dealer to other dealers, Dealers to auction, Repo yards to auction, auction to used RV dealers, some fire department trailers: everything but New factory to dealer. Zero backhauls made lots of red ink. I kinda hate used old RV tires as we left plenty of them on the road in small chunks.
We stepped out of the RV hauling into hauling auto parts and tires around the state with a cargo trailer. Kinda like UPS for auto parts, but, not hot shot. This allowed us to keep the truck, but, it was making less than minimum wage. Our parts broker couldn't pay us for two weeks so there went the truck back to the bank. Surprisingly our broker did pay up so we purchased an older 1993 6.5TD cash. Bank can't take that away. We went back to hauling parts for them, but, the fuel economy of the Asthma Attack turbo GM used made for miserable fuel economy 7.5MPG with the grades we have in AZ. Further it was under powered slow pushing DOT hours of service limits. Regardless the old 6.5 went to work because another driver blew a $1000 ECM on his Dodge truck and couldn't afford to fix it. One blown engine later we gave it up when it was totaled after hitting an elk. After rebuilding the truck we made some money hot shotting for the same parts broker now and then and hauling RV's from auction to a local used RV dealer till that small time RV broker went under and neglected to pay us as well as the rest of it's drivers. Later I got to shove an IRS audit up the auditors where the sun doesn't shine and walked away still writing off rebuilding and hot rodding the 1993. I am left with a pickup that has over 1/4 million miles, fresh 6.2 hybrid 6.5 engine, large turbo, Yank Stall, rebuilt front end, and I am missing the shirt off my back like a lot of people are from 2008's Great Depression V2.0.
As far as RV hauling there are some secrets to it. The biggest is "Hook and Tow": where you have a flat bed MD truck and haul a small trailer on the bed and tow another. The recruiters don't say s#it about this option. We only found out about it by making two trips to finish delivering loads when a hook and tow driver blew their clutch and the broker didn't give them time to fix it. Ugly situation to be blindsided with when we showed up. Hook and Tow pays slightly more for the same single digit MPG. Again RV hauling isn't what they are selling it as and I suggest other ways to make some better money OTR. I haven't seen a peep about the hidden gotcha cost the ComData card the big RV brokers use to pay you. The ComData card takes a cut of your (profit... wrong word: pay) for almost every transaction.
Far as I am concerned a overpriced new or used diesel pickup is the wrong tool for the job. MD trucks are cheaper to buy used and have longer lasting 19.5" or so tires out of the gate. I am not talking about overpriced Duramax, RAM, etc. 4500/5500 pickup look alike, but, a Frightliner or similar used from a rental company.