Salem sells its airtime as a network. So, if it can get its Spanish speaking rent-a-preachers to pay extra to be on in the market, you could easily see Radio Luz in the Twin Cities. Keep in mind that it also has enough rent-a-preachers that it can have two English-language teaching stations in a few markets, like Boston and Phoenix.
I doubt you'll see them sell 1570. Salem isn't in the business of selling stations unless it can get a fortune for them, and I can't imagine anybody spending much on 1570.