Other walks to try are "High lead" about 7klm east of Powelltown, try walking from Powelltown along Reids Tram way then High lead to Starlings Gap.
The steepest track in the Yarra Ranges National Park is the Mt Juliet track accsess is gained off the Maroondah hwy before you get to Fernshaws, last kilometer is steep and loose rocks, large stone cairn on top built possibly by British army engineers in the 1800's.
Will post a couple of other walks when done, they've been unmaintained for years, as Parks vic have little money to maintain all of them, but should link up well with others mentioned in this forum, they won't be as neat and orderly as those in the Dandenongs, but wild tracks, no formed steps etc.