If you have a high-def video camera, be sure to take it on a hike with you to the bottom of the canyon. HD is the only way to bring out the gorgeous contrast of blue sky and red rock that you'll want to show everyone at home.
I've found from experience the best and most reliable brand of adaptors for Australian travellers is Korjo. Check out www.korjo.com
I went on two tours alone...I made life-long friends along the way! That's the nature of Contiki.