I read the outline and actually liked it. There are some ways to improve it (just suggestions, really)
1. The leaving scene - it is actually great scene if written out well. Let me suggest how it should be redone - we see a not one scene, but a number of days (scenes) she prepares to leave - saving money, drawing plans, discussing staying in LA, choosing a car. (Reader is intrigued why the 17 old is so meticulously prepares her departure - it is not something which any 17 old does).
Important moment; we actually don't know if Layla is really talented. There are could be two possibilities - she has zero talent (Summer is wrong). Another possibility is that Layla is a real gem - then the script should prove that Layla is actually talented, like by having her win a local contest or something.
Important moment 2. If Layla is artistic and talented, she is probably good looking. And good looking 17 year old girl SHOULD have a kind of romantic relationship. That is totally missing.
2. Leaving scene -needs emotional connection to the home town. She hangs out with friends, family, teachers before leaving. She is sad to leave them (girl's emotions) and may drop some cryptical messages which they don't understand - and she may hug parents without telling why, just thanking for everything and or just crying. That could be a powerful scene.
3. The looking last time at the home, or parents' room - this could be a wonderful scene - she would watch them sleeping peacefully (we should see her emotions whe she silently says them goodbye). This is an important moment, when she becomes a runaway.
3. Scene of actual leaving (ride in a car) - mixed emotions of leaving friends and family yet being excited by the future. This scene should be enriched and some important details added. She could cry in the car - and yet sing or dance in the car, feeling how she gets closer to her dream. We don't have any depiction of that in the script - Layla right now seems little bit like a robot.
4. Important things are missing like what her parents and friends react (it is not in the script - did they cry? panic? what happened when they read the letter? did they cry? did they joy?), what about friends? Did they realize she left for good? What did they fell? Did Summer miss her? Did Summer think that they should left together? Did Summer tell police and parents about their last talk? (a scene of "last supper" really..). Did Summer realize the dangerous situation to which she persuaded her best friend to go?
5. Logic. What about police? Police should be immediately contacted, and probably they will or try to intercept her at the highway (cause they already should know the plate number - it is a small town, and seller would disclose that to police immediately).
6. For a girl, who has meticulously planned and executed her departure, the picking up of a stranger, who turns out to be a thief and addict, is very strange, and is not something we'd expect from the girl. What is the purpose of the scene? If it doesn't have any special meaning, it should be cut out. We already know the Kyle's line will go nowhere - so why spend precious time on something that doesn't really matter?
I think what is really important is what actually understanding the reason why Layla is leaving - is it only because Summer told her so? Maybe there was an urgent call for auditions with a looming deadline and parents would object? Why parents would object to audition - if they knew Layla is talented, what would be their reason? Why dad couldn't just drive Layla to LA? What are Summer's intentions? Why Summer did not really leave? etc.