Railside is Grand Island's old downtown core, a few blocks of brick storefronts, murals, restaurants, bars, and event spaces near the Union Pacific tracks. It will not change your trip by itself, but it gives the city a more walkable centre than the highway strip suggests.
Come for a meal, a drink, or a local event rather than as a formal sightseeing stop. In a city built around cars and long roads, Railside is the easiest place to slow down on foot.