Just got back from three weeks in my beloved home country!

Cairns to Sydney is 1800 miles of almost all single lane narrow highway with fairly few spectacular parts (nothing like California Hwy 1 except the drive north from Cairns to Port Douglas).

Frankly I would fly and devote more time to Sydney. If you really wanted to drive some of the way then try Brisbane to Sydney. I haven't hired any motorhomes but the ones in Oz are generally much smaller than the US models - I saw lots from the "Britz" company.

Highlights of the trip would be: Daintree Rainforest north of Cairns, Kuranda above Cairns, Reef off cairns, Islands off Mackay (Whitsundaes), Fraser Island - amazing lake McKenzie and rainforest (off Hervey Bay), Noosa Heads, Gold Coast (if you like Miami style tower blocks), Byron Bay (surfing and alternative centre), Coffs Harbour and hinterland and, of course, Sydney (which you should allow one full week for - you won't be sorry). If you do drive you will be able to get to all these spots - if not then fly Cairns to Mackay to Hervey Bay or Noosa then to Sydney and you will get the best bits.

June is a great time of year for tropical north queensland but Sydney can be colder (60 degrees f maximum)although usually not rainy. You will find Australia amazing value if the current exchange rate holds up - three course dinner for two with wine for around $80 US at one of the top restaurants in Sydney.