[greymule]

This is not so complicated. A fair batted ball hit a runner who was in contact with a base and did not interfere intentionally. The nearest fielder was playing behind the runner. (Whether the fielder had an opportunity to make an out is irrelevant.) Therefore, the ball is immediately dead. The batter gets 1B, and other runners return TOI unless forced.

This is ASA only. NSA's rule covering runners hit while in contact with a base is different. In Babe Ruth softball—which follows OBR—the base is not a sanctuary; the runner is out unless the ball passed a fielder and no other fielder had a chance to make a play. I don't know about Fed softball; it probably follows ASA.