Itinerary Cairns to Tweed Heads

I forgot to mention that we have four weeks to do it in. OOPS.

Paronella Park near Innisfail is worth a night. Free caravan park for the night if you pay entry fee. If you do all of the free guided tours it is very interesting. I think the kids may get something out of it.
If you head inland a bit to Emerald / Rubyvale, one or two days hunting for saphires in the buckets of ore you buy for about $8 is a lot of fun. While in the area, a free guided tour of the Blair Athol mine near Clermont is much more interesting and enjoyable than it may sound.
We left our van at Wonga beach and drove up Bloomfield track and stayed a night in a motel at Cooktown and came back on the inland road. Wouldn't like to have towed the van after seeing the track, but a true offroad van could be ok. Really enjoyed Cooktown. Undarra Lava tubes are well worth a vist but a bit out of your way, unless you decided to do the Kurumba trip. Yeppoon and Bagara Beach are good for a couple of days.

thanks for the ideas. They are greatly appreciated.