Complex sentence: Harry takes Evie back to the hotel and impulsively kisses her, but Phyllis unexpectedly arrives from Altoona, so Harry goes to stay with her in the hotel across the street, while Evie sadly arranges to return to Ohio the next day.
Split into simpler sentences: Harry takes Evie back to the hotel and impulsively kisses her, but Phyllis unexpectedly arrives from Altoona. So Harry goes to stay with her in the hotel across the street, while Evie sadly arranges to return to Ohio the next day.