Senior cat long distance travel.

We just bought a house that's 3 days trip away in the car. We need to move our 14 year old cat. We are not able to pick her up because of her trauma issues. We adopted her from the shelter hours from being euthanized at 11 years old. We don't know what kind of trauma she went through but it does bother her. We got her to get in a cage when the movers came with treats but shes so stressed and miserable. I bought calming spray but it doesn't help her. I am starting to worry she might not make the journey. What can I do or give her to help her relax enough to endure the ride ahead. She can't free roam in the car because she freaks out. I bought a cage big enough for her to have essentials and move around in. I need her to be ok with at least going in the cage. We tried to put her in today again so she could get used to it. She immediately became upset and tried to attack us. She has never done that before. It was too much stress for her so we decided to stop trying to get her in. Please help. She's too old for tranquilizers. I want her to relax in happiness of a big bay window of the house we bought. I just need to get her there