Ginger and Petunia by Patricia Polacco
There's Ginger, an artsy middle aged lady who lives with her pet pig, Petunia. When Ginger takes a trip, she leaves Petunia home alone. The fun loving pig decides to dress up in Ginger's clothes and pretend to be her! She teaches piano lessons, goes to the museum, dances the tango with the governor and goes to a fancy dinner party. Even though she's having a brand new adventure, the pig misses her mud soaks. This picture book is plenty fun!