I did this pre-DD (from Perth to Brisbane) and even took a photo every 5 minutes along the way! It is an interesting trip but you shouldn't run into many troubles, there are definitely sufficient places to stop etc. Can't remember exactly prices and such but it can't have been toooooo expensive because I barely had money to my name at that point (was only 19) and survived on motels etc for over a month. I hope you have a safe and fun trip