G`Day,
Regarding booking a camping site at Ayers Rock in advance. I personally hate doing this (anywhere) as you are committed to that particular date and could miss out on something or highlight on your travels as you don’t have the time.
My tip: Try and plan your arrival at Ayers Rock camp ground before midday as check out time is 10am and the chance of a site (even at peak times) is good. Remember most tourist’s come from "The Alice" and don’t arrive till late afternoon. As "lexini61" has already written "Curtin Springs" is an alternative (107KM from Ayers Rock) my suggestion is: stay the night, there, a public telephone box is available at the roadhouse and pre-book for the following day or there is a rest area (with toilets and a view) on the left about half way to the rock, park the night, have breakfast enjoy the view and be at the camp ground nice and early, book in and you will have the whole day to explore.
Check their web site
http://www.ayersrockresort.com.au/arrcamp/ for pricing and pre-booking click on "Pricing & Packages"
If you wish to visit “Rainbow Valley as suggested by Tina & Andreas the road in has been upgraded to a “dry weather” road and is accessible by 2WD vehicles with caution (the last 2 km of sand has been graded). The gravel road can be very corrugated and wash-outs can be a problem after rain. Check with the “main roads department” , Tourist Office both in Alice Springs or their web site
http://www.ntlis.nt.gov.au/roadreport/region.jsp?name=central_australiabefore you attempt the drive. (The road in at present has been closed due to flooding). Also check with your hire company if you are allowed to drive on maintained gravel roads as some companies I believe have restrictions.
Oh yes if you do get to “Rainbow Valley” stay overnight at the National Park camp ground (small camping fee with toilets and free gas barbecues) and enjoy the spectacular sunset… its not to be missed!!!. If you get up early, take the walking track to the north side and enjoy the sunrise!
Hope you enjoy your trip to the “Red Centre”
Kind regards, Aussie1