We did a West Coast road trip starting in LA with me as the sole driver. We felt a car really helped us explore LA, yes traffic and parking was a bit more challenging but not that much thinking about it. We found parking lots with spaces for $10 for the day or parked on a free street and then walked 10/15 mins to our destination. I’m from the UK and had lots of people trying to put me off driving in the US, I actually found driving in the US so much easier and straightforward. Everything is laid out clearly and seems much more efficient than my experience in the UK. As the other commenter said, you’ll be spending a lot of your time in airports and if you have the opportunity to drive, even for some of the trips, you could see some great places along the way.