Contact the churches in the towns with big Hispanic populations, for sure.
Any town with big immigrant-attracting industry -- Sioux City Iowa, South Sioux City Nebraska, North Sioux City South Dakota, that area has a great big Spanish-speaking population and few Spanish ministries when I was there in the 80's and 90's. Look there to see if churches are ready to expand into Spanish ministry.
Of course towns all over the Southwest, too. Santa Fe New Mexico, Albuquerque... How is your search going?