So after reading this and several other threads I have conflicting answers. A full dolly would be best but that won’t be an option. I have to use a tow dolly to tow my 08 Prius about 600 miles. I understand how to load it front wheels first but I’m not clear on how to NOT set the parking brake when the power is off and the car is on the tow dolly. Do I just drive it in the dolly and then power it off without hitting the parking brake button?
Why do you think you need to not set the 'P', which the car will do anyway as part of the shutdown sequence even if you don't press the 'P' button? If it is on the dolly the front wheels are off the ground, right?
The reason it isn't clear is that you are mixing up the term "parking brake" with the park function of the transmission. The P button (or powering the car off) activates the transmission park function, not the brake. The P function locks the transmission, and therefore locks the driving wheels, the front ones, so you don't care about that very much if the front wheels will be off the ground. The parking brake is the whole separate mechanism activated by the foot pedal at the far left. It brakes the rear wheels of the car. If you are towing with only the front wheels off the ground, then you need to be sure to release the parking brake so the rear wheels can freely turn, and there's nothing complicated about that. The far left pedal there simply has a push-once-to-apply, push-again-to-release way of working. It's purely mechanical, and has nothing to do with powering the car on or off.
