Complex sentence: Cash was surprised at how well the song went over with the audience--the rough, spontaneous performance with sparse accompaniment was included in the "Johnny Cash At San Quentin" album, ultimately becoming one of Cash's biggest hits.
Split into simpler sentences: Cash was surprised at how well the song went over with the audience. The rough, spontaneous performance with sparse accompaniment was included in the "Johnny Cash At San Quentin" album, ultimately becoming one of Cash's biggest hits.