In terms of tours, guides, and audioguides ... we never use them ... mostly because of my short attention span and the huge amount of detail.
We took the map we were given, and asked the first ranger / attendant "We have two hours or so - what are the eight best things for us to see?", and she marked them on the map, and drew a line showing the way to walk between them. There's a fair bit of walking, and steps.
