Complex sentence: Martin finished recording the album two days before an engagement at the Sands Hotel in Las Vegas, his popularity at the Sands was such that "Variety" reported that "the room could have been filled twice over for each of the two shows".
Split into simpler sentences: Martin finished recording the album two days before an engagement at the Sands Hotel in Las Vegas. His popularity at the Sands was such that "Variety" reported that "the room could have been filled twice over for each of the two shows".