Poking about in Moreton Bay and the protected waters between the Gold Coast Seaway and Caloundra will give you the opportunity to learn the ropes then if you can make it up into the Great Sandy Straits you have another large body of protected waters and from there you can day sail it all the way to Cairns or further north. There are lots of VMRs you can get
local information and
weather reports and if you graduate to more
remote coasts there are
weather reports from the Met Bureau via
HF radio.
With the semi protected waters inside the reef and lots of re-supply places and
anchorages and good weather the coast of
Queensland is probably one of the better places in the world to take up and learn the small vessel cruising
game.
Unfortunately the Shiela Net
HF radio network on 8161 at 0800 ceased operation a few years ago, it was a great place to meet other cruisers who you could later introduce yourself to in various
anchorages. You might join the Shag Island Yacht Club, it is a fun thing and I think they have a
radio network and roundup at the Gloucester
Passage every year where you could meet other cruisers.
Good luck with your plans and a cat is an excellent choice for cruising northern Australian waters.