Going out vs bedtime - please advise

My child is 4.5 months old right now and surprisingly going through the sleep regression very well. She wakes up at 6:30, has 3 naps - 2x30min and 1x2h (stroller walk). She goes to bed at 6.30pm and basically sleeps fine through the night.

Now that she is no longer a newborn and we have some sort of routine established we also want to get out of the house to see family and friends who mostly live a 1h drive away.

Please give me some advice how do you handle the drive and the bedtime? Our girl absolutely MUST have her last nap until 4pm to be neither over nor under tired at bedtime (whether it is the 2h walk or 30min nap doesn't matter)

We don't want to have to leave every time at 3pm when visiting so she can nap in the car until 4pm...

Any advice how you did socializing is welcome. Maybe we should give her a bottle at 6pm and then pack her into the car and just transfer to the crib?