Complex sentence: This ended all community activity at the site of the river ford at Rocky Point, and all the ranches and homesteads along the Missouri River, and its bottoms were sold to the federal government, and abandoned by the families who had lived in them.
Split into simpler sentences: This ended all community activity at the site of the river ford at Rocky Point. All the ranches and homesteads along the Missouri River and its bottoms were bought up by the federal government, and so they were abandoned by the families who had lived in them.