Welcome to the forum. I will start with some questions for more information.

Do you already have a Hobie and if so, what size is it?

If you have the Hobie, join a club that sails Hobies. There are many in Queensland, Hervey Bay has a good fleet and are usually very willing to help new members learn to sail. www.herveybaysailingclub.org.au/

Once you have mastered the sailing part in the Hobie, then you will probably find that the Hobie is not really suitable for island hopping in the GBR, unless you plan to do the islands very near the coast (such as the Keppels). So your next plan may be to upgrade the Hobie to a trailer sailer so you can have sleeping quarters, store food and water (no water maker required), basic cooking facilities and some shelter from the sun/wind/rain.

Feel free to ask more questions as you progress.

There was somebody a few years ago embarking on a similar adventure asking questions on this forum. I believe they accomplished it too and gave some detail of the trip.

Do a search, it might produce something for you.

Michael... maybe re-consider your goals for now? I am just back home close to Sydney after a sea-kayak circumnavigation of Tasmania's Bruny Island; 180km in 6 days and 75km around Maria Island in under 4 days. Sails were used.
In year 2000, I paddled a sea kayak 1400km alone from Tweed Heads to Townsville over a slow 11 weeks -and air-freighted the fibreglass kayak home. Sea-kayaking has directly lead to me crewing sloops on longer yacht deliveries.
With an expedition sea-kayak, the usual lightweight bushwalking gear and additional freshwater is carried in watertight compartments, solving the matter of '...sleeping quarters, store food and water (no water maker required), basic cooking facilities and some shelter from the sun/wind/rain.'

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