Water Wow! – These surprisingly keep my very busy 4 year old busy for quite a while. Plus, you can find them pretty much anywhere – Walmart, Target, amazon, etc.
Pipe Cleaners – Endless possibilities for play!
Car Bingo – Something the whole family can play! There are tons of free printable cards on Pinterest that you can simply download and print on your own.
Velcro Lollipop Sticks
Magnets in a lunch box
Plan stops – Map out rest stops ahead of time that have plenty of space for the kids to play or just run around.
Age appropriate Audiobooks or Podcasts
Snacks! Snacks! Snacks!