Who is Lil Spicer from Okay for Now and what is their importance?

Lil's family owns Spicer's Deli in Marysville, New York. Doug meets Lil on his first day living in Marysville, where he sees her riding a pink bike. Doug runs into her again on the first Monday he lives in town, and Lil offers Doug a job delivering groceries for her father's store. Over the course of the story, Lil and Doug become very close friends.