Endless runner

I have this script which generates the scene, but I need some help changing the background based on the amount of points that the player has. It would be great if someone could help, I have been told by many people to try it my self but I have been trying something for an hour now, so please don’t say have you tried it or anything else. Thanks in advance

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class GeneratorScript : MonoBehaviour {

	public GameObject[] availableRooms;
	
	public List<GameObject> currentRooms;
	
	private float screenWidthInPoints;

	public GameObject[] availableObjects;    
	public List<GameObject> objects;
	
	public float objectsMinDistance = 5.0f;    
	public float objectsMaxDistance = 10.0f;
	
	public float objectsMinY = -1.4f;
	public float objectsMaxY = 1.4f;
	
	public float objectsMinRotation = -45.0f;
	public float objectsMaxRotation = 45.0f; 


	// Use this for initialization
	void Start () {
		float height = 2.0f * Camera.main.orthographicSize;
		screenWidthInPoints = height * Camera.main.aspect;
	}
	
	// Update is called once per frame
	void Update () {
	
	}

	void FixedUpdate () {
		
		GenerateRoomIfRequred();

		GenerateObjectsIfRequired();    
	}


	void AddRoom(float farhtestRoomEndX)
	{
		//1
		int randomRoomIndex = Random.Range(0, availableRooms.Length);
		
		//2
		GameObject room = (GameObject)Instantiate(availableRooms[randomRoomIndex]);
		
		//3
		float roomWidth = room.transform.FindChild("floor").localScale.x;
		
		//4
		float roomCenter = farhtestRoomEndX + roomWidth * 0.5f;
		
		//5
		room.transform.position = new Vector3(roomCenter, 0, 0);
		
		//6
		currentRooms.Add(room);			
	} 

	void GenerateRoomIfRequred()
	{
		//1
		List<GameObject> roomsToRemove = new List<GameObject>();
		
		//2
		bool addRooms = true;        
		
		//3
		float playerX = transform.position.x;
		
		//4
		float removeRoomX = playerX - screenWidthInPoints;        
		
		//5
		float addRoomX = playerX + screenWidthInPoints;
		
		//6
		float farhtestRoomEndX = 0;
		
		foreach(var room in currentRooms)
		{
			//7
			float roomWidth = room.transform.FindChild("floor").localScale.x;
			float roomStartX = room.transform.position.x - (roomWidth * 0.5f);    
			float roomEndX = roomStartX + roomWidth;                            
			
			//8
			if (roomStartX > addRoomX)
				addRooms = false;
			
			//9
			if (roomEndX < removeRoomX)
				roomsToRemove.Add(room);
			
			//10
			farhtestRoomEndX = Mathf.Max(farhtestRoomEndX, roomEndX);
		}
		
		//11
		foreach(var room in roomsToRemove)
		{
			currentRooms.Remove(room);
			Destroy(room);            
		}
		
		//12
		if (addRooms)
			AddRoom(farhtestRoomEndX);
	}

	void AddObject(float lastObjectX)
	{
		//1
		int randomIndex = Random.Range(0, availableObjects.Length);
		
		//2
		GameObject obj = (GameObject)Instantiate(availableObjects[randomIndex]);
		
		//3
		float objectPositionX = lastObjectX + Random.Range(objectsMinDistance, objectsMaxDistance);
		float randomY = Random.Range(objectsMinY, objectsMaxY);
		obj.transform.position = new Vector3(objectPositionX,randomY,0); 
		
		//4
		float rotation = Random.Range(objectsMinRotation, objectsMaxRotation);
		obj.transform.rotation = Quaternion.Euler(Vector3.forward * rotation);
		
		//5
		objects.Add(obj);            
	}

	void GenerateObjectsIfRequired()
	{
		//1
		float playerX = transform.position.x;        
		float removeObjectsX = playerX - screenWidthInPoints;
		float addObjectX = playerX + screenWidthInPoints;
		float farthestObjectX = 0;
		
		//2
		List<GameObject> objectsToRemove = new List<GameObject>();
		
		foreach (var obj in objects)
		{
			//3
			float objX = obj.transform.position.x;
			
			//4
			farthestObjectX = Mathf.Max(farthestObjectX, objX);
			
			//5
			if (objX < removeObjectsX)            
				objectsToRemove.Add(obj);
		}
		
		//6
		foreach (var obj in objectsToRemove)
		{
			objects.Remove(obj);
			Destroy(obj);
		}
		
		//7
		if (farthestObjectX < addObjectX)
			AddObject(farthestObjectX);
	}
}

seems like it would just be an easy if statement? if points > x , then background = blue… etc?