Is someone else coming with you? if so I would take shifts sitting in the back with the baby so she's not just staring at the ceiling and has some interaction

I don't think it's bad at all of its hot keep the AC on .. And just take a few stops to take him out of the car seat.. Change diapers frequently and bby should be fine ! It's easier than when they're awake all the time

I do a hour and half drive twice a week with my 3 month old she will be 4 months tomorrow and now that she is awake more and wants to play more it's awful. she usually screams unless I plan it just right and go during her long nap which usually doesn't work in my favor. She use to love car rides but not now. If your baby still sleeps a lot I think you would be fine.