A number of years ago I towed a 3/4 ton pickup truck cross country without the benefit of a trailer. Knowing it was too big to fit a trailer, reasoning it only got 8 mpg on a GOOD day and having to choose whether to leave it behind or not, I found a reputable welder to put me together a tow bar to attach to the frame (after removing the front bumper of course) that would bolt into the existing frame holes where the original bumper mounted onto. It was allowed to hinge up and down on the frame to handle bumps and dips using hardened pins. Unlocking the steering wheel, removing the driveshaft, attaching safety chains from a heavy duty tow chain and wiring in the truck's tail lights as tow lights allowed me to drag it 880 miles from Dallas Tx to Panama City Beach, FL on the back of a 24' Ryder moving van. It even provided me with additional storage for what wouldn't fit into the moving van, such as my ride on mower.
That was back in 2008. Today I am faced with a similar move from PCB to East Texas in a little over 3 months, this time with a 73 Newport. I intend to follow the same course of action to drag my beloved Chrysler with me to my new home.
Having lived in a tourist town for over 12 years, I've seen many motor homes dragging behind them their family cars to vacation here on a similar manner. It is cheaper than a trailer and in some cases, you can resell the tow bar on Craigslist or eBay when the trip is completed.
Just a thought for you to consider for transporting a big car across long distances.