I was thinking something like Middletown. I would go with any of the following.
Middletown
Centerville
Miamisburg,
Kettering Fairmont.
Mason.
If OH$AA wants neutral site games, they should talk to member schools and say would you be willing to host instead of asking for bids.
Schools that host just make extra money with volunteer work. I was talking to guy who's son plays sports at Mason and the parents were contacted to work the game and their sports team would get money.
I looked at the lot on the south side of the field at the corner of Tylersville Rd and Foxfield Dr. I counted about 25 spots per row. Then I counted 23 rows. So at 5 bucks a spot (from what I could tell they were all full) That is $2875 bucks just for parking in one lot. They also have other lots available.
Then you have the concessions. If no one is in the stands, no concessions are sold. So they make money there too, You have volunteer workers, but you do take the risk of buying food. Overall you still make money.
The only cost you have are for the power for the lights and police. Overall if you host you will make money if the AD puts a little effort into getting the volunteers together.
I have nothing against Piqua, from google maps it looks like a nice stadium. I just wish the game was between Springfield and Elder.