When bass-heavy music that vibrated the entire car, tapping all over the inside of the frame with a hammer, and a car wash didn't work I decided that perhaps setting off a baking soda bomb underneath the car wouldn't have quite the desired effect. I've had a couple encouraging messages about snakes turning up weeks after they disappeared, thank you Emanon for your story of how my girl's mother was lost in your car for 6 weeks... apparently its genetic. So I decided that so long as I can keep the car from freezing overnight she should be alright and may just turn up in a couple of weeks asking me why I haven't fed her recently. Still leaving out water and masking tape traps but going to only put out a mouse in a bottle once or twice a week.
Thank you everyone for your advice and support. I'll let you all know if something particularly encouraging, or discouraging, happens.