Hopefully this Action will return a String variable of the Path of a GameObject.
using UnityEngine;
#pragma warning disable 168
namespace HutongGames.PlayMaker.Actions
{
	[ActionCategory(ActionCategory.GameObject)]
	[Tooltip("Returns the String of the Path of the selected GameObject.")]
	public class GetGameObjectPath : FsmStateAction
	{
        [RequiredField]
        [Tooltip("The GameObject from which you return a String of its Path.")]
        public FsmOwnerDefault gameObject;
        [RequiredField]
        [UIHint(UIHint.Variable)]
        [Tooltip("Store the final String of the GO's Path in a variable.")]
        public FsmString storeResult;
        private string result;
        private Transform tf;
        private string name;
        public override void Reset()
		{
			gameObject = null;
			storeResult = null;
		}
		public override void OnEnter()
		{
			Find();
			Finish();
		}
		void Find()
		{
            var go1 = Fsm.GetOwnerDefaultTarget(gameObject);
            tf = go1.transform;
            result = tf.name;
            while (tf.parent != null)
            {
                tf = tf.parent;
                result = tf.name + "/" + result;
            }
            storeResult.Value = result;
        }
	}
}