Simple NPC Character Movement with Mecanim

Okay, so I followed along with the Mecanim tutorial to set up an idle, running, and attack animation for a character to demonstrate the animations in Unity for a class assignment. However, I do not want the character to be controlled by the player as in the Mecanim tutorial. I was able to use this Root Motion documentation to create a simple movement along the x axis with the following code:

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(Animator))]
 
 public class RootMotionScript : MonoBehaviour {
 
     void OnAnimatorMove()
     {
             Animator animator = GetComponent<Animator>(); 
 
             if (animator)
             {
            Vector3 newPosition = transform.position;
                newPosition.x += animator.GetFloat("Runspeed") * Time.deltaTime;                                 
            transform.position = newPosition;
             }
     }
 }

This worked but the character clips through the terrain at parts and floats above it at others. I had read that CharacterController can be used to supply the slope navigation I am looking for, but it has no effect with my existing code.

As an alternative, I tried using CharacterController.SimpleMove with the following code:

     var speed : float = 3.0;
     var rotateSpeed : float = 3.0;
 
     function Update () {
         var controller : CharacterController = GetComponent(CharacterController);
 
         // Rotate around y - axis
         transform.Rotate(0, Input.GetAxis ("Horizontal") * rotateSpeed, 0);
         
         // Move forward / backward
         var forward : Vector3 = transform.TransformDirection(Vector3.forward);
         var curSpeed : float = speed * Input.GetAxis ("Vertical");
         controller.SimpleMove(forward * curSpeed);
     }
 
     @script RequireComponent(CharacterController)

With this method, the character actually falls to the terrain if placed above it, so I know that vertical movement would work, however it no longer applies the root motion to the animator and therefore will not move in the x axis. I would appreciate any guidance in executing either of these method effectively to have a simple run animation across uneven terrain.

Thank you.