Looking for must do places to see and do between Lightening Ridge and Hervey Bay.

Lightning Ridge itself. Good spot.

Definitely John Murray's art gallery, not to be missed.
Great fella, great art.

Welcome to Forum Mayzee, There are many places of interest on your proposed trip. Try looking at Camps books - note where there are many camping options that's where most people are staying for the attractions in that area.
Each State have on-line "visitor guides" that highlight their features, start there.