Problem with boat script

I got a boat script from a youtube tutorial and it works fine, the way it works is when you press 1 you go into your fps controller and when you press 2 you control the boat. The problem i have is i want it to only be able to switch when you are in a certain area, for example you have to walk up to the helm.

I tried messing around with OnTriggerEnter and Exit but im not very good at programming.

This is the script for switching modes. Any help is appreciated.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class switchMode : MonoBehaviour {
 
     public GameObject boat;
     public GameObject boatCamera;
     public GameObject player;
     public GameObject playerStartPos;
 
     // Use this for initialization
     void Start () {
         
     }
     
     // Update is called once per frame
     void Update () 
     {
         //set to boat mode//
         if(Input.GetKey ("1")) 
         {
             boat.GetComponent<Rigidbody> ().isKinematic = false;
             boat.GetComponent<boat> ().enabled = true;
             boatCamera.SetActive (true);
             player.SetActive (false);
         }
         //set to boat mode//
         if(Input.GetKey("2"))
         {
             boat.GetComponent<Rigidbody> ().isKinematic = true;
             boat.GetComponent<boat> ().enabled = false;
             boatCamera.SetActive (false);
             player.SetActive (true);
             player.transform.position = playerStartPos.transform.position;
         }
     }
 }