What's the Name of That Book??? discussion

I just realized that there was a book I liked in middle school, but I don’t remember the title. Does this ring a bell to anyone?
-secular teen fiction; not a very long book
-I was in middle school around 2012, but this book felt a little older. Like 2004-2006?
-main girl was possibly named Dixie?
-author might have been Paul something-or-other?
-the cover showed a close-up of a red car. Maybe a green/blue background
-the plot followed the MC as she stole said car from her mother and drove across the country. (I think they’d recently moved; and her estranged dad could have been involved somehow)
-she stopped to eat at a gas station in the Midwest at one point, but might have gotten sick from it?
-it was mostly told through letters, postcards, etc.
-I might be getting this next part mixed up with another book. But I think she had a friend whose mother was abusive and mentally unstable. (At the end, they might drive the mother's truck into a lake??)
I know it’s weird and vague, but if anyone can help me find it, I’ll be so happy!

Searching: young adult novel "steals her mother's car" "cross country" this book came up:
Defining Dulcie by Paul Acampora


Reader reviews:
-When Dulcie's Father accidentally kills himself, it's a bit of a shock. When her mother decides to move them off to California, it's more than Dulcie is prepared to take. When she finds out her mother intends to get rid of her father's truck, she officially draws the line: she takes it and drives herself back to Connecticut.
- Little by little, Dulcie learns about Roxanne's horrific home-life...a physically and emotionally abusive mother, a filthy home, and a sub-standard life.

Yes!!! That’s the one! Thank you so much