Best case, there's a closet, hallway or bedroom on the other side of the wall. Drywall there is quick to open and patch, and some homes already have an access panel waiting.
From the shower side, the opening can often stay inside the area a trim plate covers. New valves tend to ship with smaller round or square plates than the big oval ones on older valves, so a wider remodel plate is common when an old valve comes out.
What's under the floor matters too. In a house on piers with a crawl space, the drain and the lines feeding the shower can often be reached from below. On a concrete slab, the drain sits in the concrete, so drain work means opening the floor from above. Valdosta has both kinds of house, so it helps to say which yours is when you call.