We arrived there after 2 pm, on 2nd week of October. So, there was no shuttle. We drove to the Devil's Postpile parking lot then did the round trip 0.8 mile hike, which is pretty easy. You can continue the walk for another 1.5 mile to reach the Rainbow Falls but we decided to walk less. The Postpile is formed only in a small area as exactly seen in every picture; that's it. Then we went to the Rainbow Falls parking lot and did the 2.6 mile round trip walk, again its very easy. The Falls is very pretty and on the way you will see the traces of damaged trees by forest fire and storms. We have also seen some Fall coloration. You may go down by stairs to enjoy the Falls, which I suppose is very exciting though we missed it since I was quite tired after the whole day drive from Bay Area. When you are ready to go back, keep 15-20 minutes time to stop at the vista point which is located at the outside of the immediate left of park entrance. You will definitely enjoy the view.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.