The wheels are turning, but they're doing it all wrong

I found a script that can make the car go back and forth, but it moves very slowly and the wheels drag across the ground unless they're moving down the ramp, so I'm clearly not doing it right. I also tried to make an object that always rotates in the direction of the player. This would be used as a gun that shoots slow-moving bullets at the player that are moderately easy to dodge but would still provide a challenge combined with platforming elements. That didn't work either, as it rotates in 3D instead of just 2D and the script is so simple that there isn't much to play around with to get it to work right. 

Lastly, I tried to make a ferris wheel platform, a large "+" shaped structure that rotates with normal-sized child platforms on all four ends that move with the structure but retain their original rotation of 0. This would allow the player to board one of the platforms and move in a circle to reach another platform, possibly another ferris wheel that's moving in the opposite direction. unfortunately, this didn't work either. I tried to add rigidbodies to the platforms and check "fixed angle" so they wouldn't rotate with the parent structure, but they developed a mind of their own as they drifted off the main structure and started rotating in all sorts of weird ways. My next attempt was to apply the rotate script to the misbehaving children and set them to rotate at the same speed as the main structure but in the reverse direction, canceling out their rotation. Now they appear skewed and misshapen and I have no idea why. 

So that's what I've been breaking lately. Tune in next week when I cause every game object to form a deadly alliance and beat the player character senseless for no readily explainable reason.