I used to work with a former State Police mechanic, and I see you're in PA so this will be good news for you.
They beat the piss out of those cars, but the mechanics took real good care of them.
All Motorcraft parts. Oil every 5k, all other fluids every 30k (coolant, PS, ATF, and differential). Brake pads every 25k whether it needed them or not, and new fluid then too. Turn the rotors at the first pad change, swap the rotors on the second. Shocks & springs at 100k, fuel & air filters at 30k.
I can't testify how well the local PD maintains their cruisers, but you really can do ok with a Statie vehicle. I would assume there to be a State surplus auction out your way somewhere, but if not, they run it over my way just north of Harrisburg about 2-3 times/year. Should be about a ninety minute drive for you, very likely much less if you drive like I do
Last cruiser I bought at one of those auctions was in 2006, got a 98 P71 with 165k on the dial for $1600. Bet nowadays you could probably find an 05+ model for ~2-3 grand, and yes, I would mirror TicTacTone's sentiment about that being the ideal range of years.