This might be how it works out. Negotiations will need to take place during thanksgiving I think
I’m going to assume there will be many truck stops, diners, coffee shops and gas stations on the way. Perhaps sweeten the deal with a lunch or breakfast offer or pay for coffee/refreshment breaks.
The both of you will also have to stop for bathroom breaks. This could play into your hand – just tell your sis you’ve had a weak bladder as of late and have been going to the bathroom more than usual. I’ve used this card more than a few times on road trips with non smokers.