There'll likely be weight restrictions for carry on luggage depending on who you're going to fly with here in Oz Carole, and even if that is all you bring, it'll depend on numbers for the SOF flight back as to what can go on, what you can take etc.

So if you have stored anything somewhere in Cairns, it'll probably be best for you to pick that up on way to Yungaburra and determine whether you backtrack via the Kennedy highway route or do the shorter Gillies route.
Doing it on the way up will at least be one way of helping you decide which way to do your return.

My earlier suggestion of ditching your rental in Cairns would have only been a savings if you had been able to reduce your car hire by one day, but seeing as that is unlikely to be the case you just have your gear after picking it up until leaving tha car at the airport.

Yes.

Bushranger - I'm assuming we'll fly on Virgin Blue... unless Qantas has a domestic airfare sale.

Thanks Saltuarius... got it.