Missing Persons series by M.E. Rabb (2004)

Comprised of The Rose Queen, The Chocolate Lover, The Venetian Policeman and The Unsuspecting Gourmet, the Missing Persons series is about two sisters who go on the lam after their father dies to avoid being sent away to boarding school by their evil stepmother. They end up with new identities in a quirky small town, and mystery and adventures ensue. Filled with eccentric, endearing characters and featuring a realistic relationship between the sisters, plus decent little mysteries, these books are great fun.