Brisbane to Cairns is 1705 KM's or 1059 Miles.
There are plenty of towns along the Bruce Highway (the coast road) and lots to see.
If you plan on stopping and looking around during the trip I would allow at least a week to 10 days for the trip. It is a long drive.
Food is no problem. KFC, MacDonald's, Pizza Hut are all here.
Every place you stop there will be something to see. The beach all the way up is very good.
BUT one word of warning about the Beaches in Australia. We have life guards and the put flags down on the beach where it is safe to swim.
DO NOT SWIM outside the flags or on unpatrolled beaches. The RIP's will take out to sea.
WE loose a lot of American Tourists in the RIP's So be very care full when swimming in the ocean.
Take a look at Google map.
http://maps.google.com.au/maps?hl=en&tab=wl
Get Directions. and type in Brisbane in block A and Cairns in Block B .
It Will show you all the places on the trip. ZOOM in for more detail.
Google a place name for T.I.