While she is unsupervised in the therapy pool, Claire attempts to drown herself. Any reputable rehab center would have had a lifeguard on duty and certainly would never leave a disabled woman alone on the deck.
Claire's laying down while riding in cars seems to be attributed to her physical injuries, but it is actually a sign of PTSD from the accident that caused her physical injuries.
Although there is a working Drive-In Theater in Riverside (California), the closest train tracks are about a mile away; making the scene showing a train passing near the screen impossible.
When Claire meets the girl who is on her way to Hollywood to become a star she asks where she is from. She says Boise, pronounced BOY-zee. Anyone from Boise would pronounce it BOY-see.
Claire's pain appears to be in her legs - it was said she had pins in her legs - and during the swimming sequence, they show a long scar that runs from above to below her knee. If it were this injury, she would not be able to squat down to slip into the pool and if it were as bad as indicated, she would have a harder time walking. Additionally, it wouldn't require her to lay down in the car during her travels.