The Grampians is an iconic wilderness area in Victoria.  There are so many tracks here and because its a relatively far distance from Melbourne it's not too overcrowded.  Be warned that it will get busy on public and school holidays but that shouldn't be a surprise.

View of the Grampians, Victoria, Australia
Some highlights in the Grampians include:

Boronia Peak
Walking in the Grampians
Information from external websites visitor guide to the Grampians (Link last checked 15-Nov-2019)