The road is slowly being sealed. Check the TMR website on current locations for roadworks.
I first did that leg in a high clearance soft-roader when none was sealed and had no real issues. I think the full length is on Google street view. Porcupine Gorge is a must see.
This link gives everything else I can say so there's no use typing extra.
http://www.visithughenden.com.au/road-reports-and-conditions