Maybe its time for her to invest in a used mini van and buy insurance. She can load it up, do the move to the first stop, then continue on to the final destination, and will still have a vehicle to drive. Use it until it dies, or sell it when she is done using it. Renting different vehicles through this entire process doesn't make much sense to me.

The next option would be to rent the vehicle and go the the final destination with the things she needs to move. Then turn in the truck and pay the one way fee, then rent a vehicle to go back to the mid stop, and driving she will do after.

The entire process is a life skill on how to plan things and life skills about learning financial skills in the real world. Dad shouldn't be figuring this out or paying for it. She needs to learn this stuff by personal experience, or she may never get it.