Are you asking specifically for a road trip, or is this a more general question about when music ownership becomes unreasonable? They are very different and my small brain can’t tell which you are asking
Nothing about a road trip. I’m moving (some day). And I have a lot of records, seemingly more than I can realistically listen to in my life esp if I plan to listen to some of them multiple times (I do)
I don't think this is a question of what's reasonable, as much as it's a question of what will keep you happy. You can take the same approach I did (aka the Philistine approach) and digitize everything, or you can decide to move everything, or decide to cull the collection. What makes you happy?