Complex sentence: However, they found no crossing to the Barun and so they headed south down the Hongu glacier and were eventually able to reach the Barun but were too far south to reach Pethangtse in the time available.
Split into simpler sentences: However, they found no crossing to the Barun and so they headed south down the Hongu glacier. They were eventually able to reach the Barun but were too far south to reach Pethangtse in the time available.