Prius will be sitting for a few months and it's old

You don't really need to drive the car at all, in the interim.

Once a week make the car READY and leave it with the parking brake set and in P for 30 min. At the end of that bring up the Energy Monitor screen on the MDF and see how many bars are showing. If it is less than 6 (colored blue), then, with the parking brake still set, press the foot brake, put the car in D, and push the accelerator pedal just enough that the engine starts (and hold it there). As soon as the battery indicator just shows the 7th (green) bar, release the accelerator pedal, put the car in P, and shut it down. That's all there is to it.

If you do take it for a drive down your private road don't be forced to back up on battery for about 1/12 of a mile. Just take a chance to go on to the main road and do a quick U-turn so you can drive forwards up your private road. I'm sure the state troopers will not be staking out your drive to make sure you not driving an unregistered car for a couple of yards on the public road.

 

When you push the start button and the car starts properly the word READY appears in the dashboard. Then you know the car has started and ready to drive. The word READY is because sometimes the cars engine does not start which is normal so they gave you that indicator to tell you the car is on let’s go.

The battery indicator on the mfd shows the hybrid battery battery charge level. You can see how full or empty it is. It goes from full white screen which is empty to one or 2 purple bars which is hardly charged to blue bars which means it’s filling up. There are 6 blue bars then when it’s full they all turn green.

You have a lot of reading to do. Go on YouTube there’s hundreds of Prius YouTube’s on a G2.

Pay attention to the hybrid battery rebuilds. You will be going there sooner or later.

 

7 total cant remember. My brand new battery lives at 4-5 blue bars. It easily goes to full green.

Purple bars are not good then if its real bad it will have 1 red bar then no bars. You will not have to drive it if you power brake it like dolj said. That works good.

It really doesn't matter because if it has 215K miles and has the original battery its going to need a hybrid battery soon anyway.
Hundreds of battery rebuild posts on this site. Start reading.

 

There are 8 bars in total.

 

You might want to do the actual driving thing, as there are other issues that can crop up from a long time sitting vehicle, like internal corrosion build-ups and freezing brake rotors. Actually driving the car moves lubricants and oils around in otherwise stagnating parts of the car.
BTW, backing the car up for 1/4 mile every time would serve as a good regular load draw on the battery, since all reverse motion is done by the electric motor exclusively. If you are ginger on the gas, the ICE will kick on to charge the batt while doing so, but if you are careful and gentle with it, you can use the run to do a deeper level of discharge to the battery with every run.
It is just a matter of how comfortable you feel with driving a car backwards.

 

True enough. Once a month ought to do it in addition to the weekly regime.