Forcing EV mode

You won’t be able to drive it on EV mode. Due to all the restrictions on the EV mode, and lack of battery capacity to drive it very far. You should tow dolly or hire a professional wrecker to move it any distance.

 

If it’s hydrolocked, take the cowling off and remove the spark plugs. If you can turn the engine over by hand, you can get to ready mode and drive it that 100 feet.

 

When mine grenaded in July the crankshaft still turned.

 

Unless you get in Ready mode the parking pawl will stop you from pushing it unless you put dollies under the front wheels.

 

There is no startermotor on a Prius so you won't find a relay of fuse for that. The eninge is started through the HSD's electrical motors.

Using EV mode is tricky because it is not a guarantee the engine will not start. It will start when the HV battery is low or the coolant temperature is very low (freezing). No idea about the state of the rest of the car, but a defective coolant temperatur sensor might screw you there too.
And the engine will come on when you press the accelerator too hard (going uphill like you need to do) and when the HV battery runs out of juice (mentioned already).

The best option is to get the car in Ready mode and immediately put it in Neutral. That way you will 100% prevent the car from starting the engine. In the worst conditions, the engine will be started pretty much directly when it gets in ready, so you might want to try starting while holding the shifter in the N position.
You can't drive the car in N of course, you'll still have to push/tow.

Otherwise put it on dollies and push/tow.

 

There's a way to get into Neutral without entering READY mode. I did it once, but inconveniently have forgotten the routine to make that happen.

 

Push the button 2x without touching brake pedal and shift to neutral.

 

The Gen 2 had a trick where if you could get it to power on and shift into neutral, pulling the P Con relay under the hood would leave it in neutral once powered off.