Complex sentence: Priestess was joined by Murder By Death and Clutch on their North American 2007-2008 tour, and traveled with GWAR and Cattle Decapitation for a Spring 2009 series of dates in the US.
Split into simpler sentences: Priestess was joined by Murder By Death and Clutch on their North American 2007-2008 tour. Priestess toured with GWAR and Cattle Decapitation for a Spring 2009 series of dates in the US.