Complex sentence: At this point, Margaret and Fred decided to run their own trips using wooden dories, which they purchased 3 from Keith Steele who used them on the Mackenzie River in Oregon, and they modified them for use on the Colorado River.
Split into simpler sentences: At this point, Margaret and Fred decided to run their own trips using wooden dories. They purchased 3 from Keith Steele who used them on the Mackenzie River in Oregon, and they modified them for use on the Colorado River.