I back up my toad all the time BUT it only has two wheels on the ground (click on "How I tow" below). Yes, the back wheels are off the ground.
When I pulled my hunting jeep behind my PU it towed better with the steering locked. I would back it up (homemade tow bar) but after a few feet in a turn it would slide the front tires. I'm going to agree with the OP that it can be done BUT the husband needs to be in the toad with the engine running (power steering), thumbs on the outside of the steering wheel, and a tow bar with arms larger than 1.5" which rules out most tow bars.