Complex sentence: He buys a wig and a dress in a clothing store to impersonate one of Sheeni's "friends", fooling Mr. and Mrs. Saunders and gaining passage up to Sheeni's room.
Split into simpler sentences: He buys a wig and a dress and impersonates one of Sheeni's "friends". He fools Mr. and Mrs. Saunders and goes up to Sheeni's room.