Complex sentence: Wilson was playing and arranging for Art Paulsen's band at the New Yorker Hotel when he met his future wife Gertrud who was from New Jersey and had been working at the World's Fair as a hostess.
Split into simpler sentences: Wilson was playing and arranging for Art Paulsen's band at the New Yorker Hotel when he met his future wife Gertrud. Gertud was from New Jersey and had been working at the World's Fair as a hostess.