West Kimberly
Derby, (2WD)
Derby is the start/end of the Gibb River Road, A large town with a good hospital, There is a very good caravan park there.
Also consider the Dumbara caravan park. It may not be as nice, but it's much safer.
Go down and see the wharf, there are 11 meter tides! It's amazing.
Fitzroy Crossing (2WD)
The Fitzroy River is WA's largest river (700 km long). When the river floods it becomes and inland sea.
Be sure to take the cruise on the Fitzroy River operated by WA Parks and Wildlife
The Fitzroy River Lodge Caravan Park is lovely to stay at.
Cape Leveque (2WD)
250 k's North of Broome (and the road is now sealed) is some of the most beautiful scenery in the West. The Kooljaman Resort is temporarily closed, but you can stay at Cygnet Bay Pearl Farm. This place has no stingers even during summer. It's also worth a visit to the Hatchery at One Arm Point. On the way up or on the way back call in to the old churches in Lombadina, and Beagle Bay.
A 4WD can be an advantage to explore the region.
Horizontal Falls
This is a high light of your trip!
The flight costs around $800 per person, but totally worth it. You can fly from Broome, but it is cheaper to fly from Derby.
You can even book an overnight stay. We've not done it, but those that have, have thoroughly enjoyed it.
As a pilot, I really enjoyed the flight and the whole day. For more info Horizontal Falls