What are your favorite things for a roadtrip with a 3.5 year old that I can Amazon Prime?

I was really hoping on a Leappad, but they're reviews on Amazon are lukewarm. I have my own Kindle Fire that I never use...how can I adapt that for DD?

I'm mostly looking for small items I can give her along the way. I was thinking magna doodle, but looks like boogie board may be a contender?