Hey snap. I have also been travelling for the last year and living off dividends, interest and investment property rent. Currently in the Caribbean sailing with no plan to come home.
I am also in a similar position with tax.
I will be selling some shares I am currently down on and then buying some of them back (The ones I want back anyway). This will reduce CGT.
Yes the first $18000 of income is tax free but chances are much of your dividend income won't be included as it would have been paid fully franked.
Irrespective it's a good problem to have isn't it? Having to pay some tax despite not working.