Sorry this is long - I need advice.

My husband's family live about 4.5 hours away. He wants to drive down this Friday after work and stay the weekend. My son is 7 months and goes to bed around 6:45pm in his crib, wakes at least 4 times at night (the first as early as 9); I usually feed him 3 times at night; trying to get it down to 2. I'm still sleep training for wake-ups because he seems to heavily rely on nursing to soothe back to sleep, even though I put him back awake in the crib.

Our bedtime routine is nurse, bath, diaper, book, crib. Nursing is separated from crib by about 30 minutes.

How badly will sleeping in the carseat at night until we get there (he'll have a crib) mess us up? He always sleeps in the crib at night. Should we wait until he's asleep to leave, or do bedtime routine, then put him in the carseat and go, hoping that he will fall asleep? Or skip bath and leave after his last feeding? I'm a stickler with bedtime - and hate this idea of going, especially with daylights savings lurking. I thought pushing bedtime back ~15 minutes a night for 4 days before would be good, but now with this trip I don't think it will work. Please help. I'm really afraid of this trip. We haven't discussed the ride home yet, but it will probably be during the day.