From Birdsville to Maree - sounds like you are heading down the Outside Track. If so, stop and have a walk amongst the gibbers and don't miss a walk through some of the Dunes. You will be amazed at what you see. Here are some ideas I am sure you will enjoy;
When in Innaminka try to go on the birdlife cruise - the amount and variety of birdlife will amaze you and you will also get to see Kings grave.
At Birdsville, go for a walk around the Race Track, visit the Working Museum and definately go out to Big Red.
Try a book at flight at Maree and look at Lake Eyre from the air.
Camp at Coward Springs, enjoy the outdoor spa and visit the mound springs nearby.
Camping at Farina Downs is well worthwhile as there are Afgan graves nearby.
Enjoy - I know you will
If you dream it - you can do it