It kinda feels like this..
..like I'm always taking up two lanes and --given my inexperience-- should be followed by a police escort. (Fortunately, we were able to get around this guy. He was hauling the bed for a really large dump truck).
My Ram 2500, unhitched averages about 19 mpg, hitched I've been getting around 11 to 12 mpg. If the road is very hilly, it can drop to 10mpg. It has a powerful 6.7L diesel. There are times I actually forget I'm towing this behemoth until I glance in my rear view mirror and have a mini-panic attack thinking I'm in Jurassic Park being chased by a T-Rex.
To date, I've spent $476.75 on diesel.