Explaining Australia to Americans?

We are Australian and getting married on Hayman this year. We’ve invited about 30 of our friends from America, none of them have been to Australia.

We included a page on our wedding website with basic information on which airport they need to fly into to get our wedding, which cities are best to fly into beforehand etc. but there seems to be some major confusion from them.

No one seems to realise how big Australia is (wanting to see the outback for a few days and then travel to Hayman) etc. They just don’t seem to know what they’re in for at all. What extra information should I include to help Americans understand Australia and how to plan their time here?