Complex sentence: Cyrus composed many of the songs on "Breakout" as she traveled on the Best of Both Worlds Tour (2007--08), co-writing eight of the album's twelve songs; two are covers, and one is a remix.
Split into simpler sentences: Cyrus composed many of the songs on "Breakout" as she traveled on the Best of Both Worlds Tour (2007-08). Cyrus co-wrote eight of twelve songs; two are covers, and one is a remix.