Hi Dave,
If you're doing the Bonnet twice daily I'm sure it won't be long before you feel like hitting Huon Road. Perhaps from town, up Strickland and then to the schoolhouse at Neika. Once you're past Ferntree it's pretty flat and really fast. The hardest bit is just up from the Ridgeway turnoff, but if you do the bonnet regularly it won't bother you.
I can't wait to get back down there. Canberra is pretty good for cycling but hot, dry and dusty in summer and cold dry and dusty in winter.
cheers,
Anthony