No, they make it to the very edge. Reepicheep is able to keep going, but Lucy, Ed and Eustace make it far enough in that they have a special talk with Aslan. That's the scene where Ed and Lucy learn that they can no longer return to Narnia, much like Peter and Susan were told in 'Prince Caspian'. That for them, the door to Aslan's country lay in their own world and that they had to find Aslan by his other name in their world.