i have just spent the last 6 months going to Carnarvon Gorge while we built the visitor center.
there is 17klm of dirt with many big rocks and very lose surface, 3 creek crossings, and very exspensive to stay, there are 2 options Tarakka camping and The Logde which closes from nov to feb i think. 200+per night, exspensive meals. if traveling from Roma its 2.5hours, last fuel available at Injune 1.5hours from the gorge, or the other side is Rolleston about 90klm.
best u drive.
only time you can camp in the National park is at school holidays, to check 07 49844505
ps its a total of 43 klm from the turnoff and there are also about 5cattle grids, cows roam freely all the time