Dingy?

It's fine. With the front wheels on a dolly the gear doesn't really matter. It will shift itself to Park when you turn it off in any case.

Just remember *not* to set the parking brake: that locks the rear wheels.

 

You cannot flat tow a Prius (well, actually Bob Wilson did it once, but its really not a good idea), but you can tow on a dolly with the front wheels off the ground. The issue that I see is that there is not a lot of clearance between the rear bumper cover and the ground, so you need to be careful of dips where you could drag the body work with the Prius front wheels up in the air. I think some dollies are lower profile than others, so you would want a low profile dolly if possible.

 

Seconded. I used to own Subarus (and my wife still drives a Tribeca,) so I'm familiar with the nervousness about towing with front wheels up. The good news is that you don't have to worry about drivetrain issues as a result of nose-up towing. As stated previously, you may need to worry a bit about departure angle and body work.