You can not go much further north in WA than the positively spectacular Mitchell plateau which features Mitchell Falls. An area rich in Aboriginal heritage. Access is over rough terrain and you must have 4WD with high clearance.
All Aboriginal sites are protected so you can not touch the Aboriginal artwork in the area but you can have a look. The most interesting flora in the area is the Livistonia Eastonii palm which grows among the Eucalypt forest.