We use a variety of stuff.
If we are looking for powered camping sites, then we will use the NRMA guide. Been using that for nearly 30 years and only got a dud place and that was from the accommodation guide where a 5 star motel turned out to be a doss house and one caravan park clearly didn't rate its stars. Apart from those two, very useful.
We now tend to look at the Camps Australia book, but find it of mixed use. It is okay on the well travelled main routes, but camp sites can be thin elsewhere that we go. Not a reflection on the guide, just the usefulness to us.
Probably next is the online State forests, National Parks and State Recreation area sites.
Online, we also use google maps and whereis for getting distance, although both can be extremely cantankerous about routing and seem to loath gravel roads.
The long term basis has been an extensive collection of maps. Initially started for bushwalking with detailed topographic maps, then I switched to the 1:100K series for bicycle touring, and then we started to accumulate regional maps from all sources for the van and now Nav based trips. Generally now, I'm biased towards Hema maps but I'd swap in an instance if someonestarted printing maps that didn't dissolve in high humidity.
The only "guide" book we have is a dated Cape York book, which was useful. Generally I loath regional guides as we are not the market they are aimed at. In future, we might pick up a few trip guides,but given the online sources of information these days, they would have to be excellent to be purchased.
As to the other side of how to go camping, etc, I sort of picked that up over the decades from scouting mainly. I do have a good collection of scouting skills books. at one stage, they were the best book for beginners. Do not know if it still holds true. I assume the Ron Edwards(?) bush craft books still exist although most of that isn't practically useful in an ongoing role.
Cook books, try the scout shops again. At one stage, they were the best for books on good reliable tucker, which is really all you need. Just about everything else is pissing in the wind to sell some contraption.