I'm not really at the opposite end of the State, but if you imagine a triangle of Pensacola, Jacksonville, and Miami, its about 360 from Pen to Jax or from Jax to Miami, a 500 mile (mostly swim) from Miami back to Pensacola. I'm closest to Pensacola.
Tucker Milling has corn and soy free options, but I don't believe they distribute as far as Jacksonville...
Check with The Feed Mill in St. Augustine, they may have an option for you, or be able to direct you further. The two big feed stores in Jax that I know of, one is a big Purina Carrier, and I don't know what the other stocks.