OP
Why do you make a 12 hour drive vs a 6 hours? Why overcomplicate this?
Why putting your gd through 6 hours of car drive taking her to your house? That is totally unnecessary.
If I were your exsil, I would be very unhappy about that.
As a person, getting stuck in a car for 6 hours a month for a visit I am forced to go would suck too.
What is more important, spending quality time with your gc or taking her to your house?
I hope the new PM is kind to Larry the Cat
What would Jane Austen have made of Gransnet?
. Some good suggestions have been made already and I hope that you'll be able to find a better way of managing the journey to see your GD.