There is plenty of information about the Gibb River Road on the web and some of it is good.
Derby Visitor Centre produce a very good booklet titled Gibb River and Kalumburu Roads Travellers Guide to the Inland Kimberley and Mitchell Plateau.
This Trip was done some years ago, however, the essentials of the experience haven’t changed.
This Trip along ‘the Gibb’ was part of a longer Adventure Downunder.
If time is available the Mitchell Plateau is a really worthwhile addition to the trip along the Gibb River Road.