Complex sentence: In the summer of 2015, Grimes toured with Lana Del Rey for several of her Endless Summer tour dates and toured into the fall of 2015 as the headliner of her own Rhinestone Cowgirls Tour with opener Nicole Dollanganger.
Split into simpler sentences: In the summer of 2015, Grimes toured with Lana Del Rey for several of her Endless Summer tour dates. She then toured into the fall of 2015 as the headliner of her own Rhinestone Cowgirls Tour with opener Nicole Dollanganger.