9 hour road trip at 36 weeks?

So this will be the last chance my husband has of seeing his family. Unfortunately, it's a 9 hour drive - probably a little longer considering pit stops. We'll be staying for a week, and then 9 hours back.

Anyone have any advice? I know it won't exactly be comfortable. Anyone have long road trips while so pregnant? What helped you?

It's not approved by the doctor but I know plenty of people have done it. I hear some recommend against it but it's a trip we need to make. I'll be able to lay in the back a little too