"Will it play in Peoria?" is a phrase that means whether or not something will be accepted or well-received by ordinary people or a general audience. Peoria is a city in the United States that is representative of middle America or the heartland.
So when someone asks, "will it play in Peoria?" or says "let's see if it plays in Peoria," they're wondering if something like a movie or TV show, product, or idea will be popular and successful with average people, especially those who live in the Midwest, where Peoria is located. It's like asking, "will people in middle America like this?" or "will this be a hit with everyday folks?" The phrase is often used by marketers and business people who are trying to gauge whether their product or service will be successful in a broader market.