"Must see"? Not so much IMO, but there are certainly some good stops on that route
I don't count Southport and environs as one, but some would do so. Crowded and loaded with rental jet ski type activities, parasailing, "thrill rides", etc.. Gack..
The Tweed river is accessible, and offers anchorage.
Byron Bay is a good roadstead anchorage in winds from the southern quadrant, right through the west. Can be rolly for monohulls, but that shouldn't bother you.
Richmond river also offers anchorage, but has a treacherous bar. Be very sure of bar conditions before entering.
The Clarence entrance is much better, and the river is scenic and little used by yachts. Excellent anchorage in Iluka, and the trip up to Grafton is very pleasant. Highly recommended!
And then it is only a day hop to Coffs...