Anyone pull a 14k 5er with a gas engine

Sure, it can be done. I used to tow trailers that weight, and more, with a 1/2 or 3/4 T truck on the farm all the time. With no brakes and on dirt roads, too. Yes, it was only a few miles and generally at no more than 30 mph. :B Will all depend on how far you're going and the terrain involved. Flat country for 100 miles? I'd do it. Here in AZ, heading to the mountains? Only if there was no other way.

Lyle