Brisbane to Cairns- Advice Please

Hi there, Early in the new year( yes- school holidays, bad move maybe) i'm planning a big adventure of camping,fishing and scuba diving from Port Macquarie up to Cairns, staying as coastal as possible, and i'm looking for advice and ideas from Brisbane onwards. My first question is, if i go to Noosa, am i able to drive from there staying on the beach more or less to Fraser Island? ie through the Great Sandy National Park along the Cooloola Coast to eventually get to rainbow beach which i believe will then get me a ferry across to Fraser. I appreciate i may may not be able to drive directly on the beach all the way from Noosa, so if not, which roads or detours should i take?
I then after 3-4 days on Fraser would like to leave from the Hervey bay side and continue north to perhaps 1770/agnes water/deepwater n.p and eurimbla area for another few days. How's the plan so far? From there onwards, i haven't planned anything or anywhere, so please, if you have some good spots that aren't a secret, i'd be extremely greatful for any suggestions, in particular camping spots close to or on the beach. Still tossing up between a rooftop or oztent.
I have a Landcruiser Prado with brand new bf goodrich a/t tyres, with a lovell/bilstein suspension kit raised 2 inches. Although there are many more things i need to buy, i hope thats a good start as far as modifications go. Should hold up pretty well in the sand i hope. I could write for hours, so i'm gonna stop here and eagerly wait any replys from you seasoned experienced folk. Thanks in advance to anyone who may reply to this thread.
Cheers, Peter.