Complex sentence: Allard has claimed to have made a total of 3 expeditions in the regions described by Edwards, following the San Emigdio Creek through the various canyons, the most successful of which was accompanied by three colleagues from Moorpark College and Carnegie Mellon University.
Split into simpler sentences: Allard has claimed to have made a total of 3 expeditions in the regions described by Edwards, following the San Emigdio Creek through the various canyons. During the most successful expedition he was accompanied by three colleagues from Moorpark College and Carnegie Mellon University.