Hoge.cs

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

public class Hoge : MonoBehaviour
{
	public List<Vector3> Points;

	// Use this for initialization
	void Start()
	{
		Verbose();
	}

	// Update is called once per frame
	void Update()
	{
	}

	public void Verbose()
	{
		foreach (Vector3 point in this.Points)
		{
			Debug.Log(point);
		}
	}
}

HogeEditor.cs

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

[CustomEditor(typeof(Hoge))]
public class HogeEditor : Editor
{
	Hoge Source;
	int ChildCount;
	bool ShowPoints;

	void OnEnable()
	{
		this.Source = (Hoge) base.target;
	}

	// Use this for initialization
	void OnInspectorGUI()
	{
		/*
		// does not work...? how to print?
		this.ChildCount = this.Source.gameObject.transform.GetChildCount();

		this.ShowPoints = EditorGUILayout.Foldout(this.ShowPoints, "points");
		EditorGUI.indentLevel++;
		for (var i = 0 ; i < this.ChildCount; i++)
		{
			var child = this.Source.gameObject.transform.GetChild(i);
			this.Source.Points[i] = EditorGUILayout.Vector3Field("point" + i, child.position);
		}
		*/
	}
}