Hi Red Leader
I have done this stretch a few times, up to Capertree for the Rage Rally - this was back in 97/98/99.(its a great gig). This is what it was like back then - it may have changed a bit since ( probably not too much.)
1. Heading south from Oberon, you have some good blacktop all the way through Black Springs almost to Porters Retreat.
2. Dirt then for about 30-odd kilometers, until you reach the Abercrombie River. Without a word of a lie, this stretch of dirt ( back then ) was like the Hume Highway of dirt roads. Hardly any corrugations, no potholes, good camber, and good vision through all corners. Mind you, after rain it could be a very different story. I got the distinct impression that this section was graded on a very regular basis.
3. The drop down to the Abercrombie River is really quite frightening. Caravans are banned, for good reason. You climb out at almost a 1-1 grade !!!

Its OK on a bike, but you need to go very carefully.
4. A little bit of tar either side of the river, then back to dirt for about another 30?km of dirt until about 5?km outside of Taralga - there is a great pub on the RH side ( heading south), they have good tucker, and some good pinball machines !! The dirt stretch up to Taralga was very similiar to the first stretch from Porters to Abercrombie River.
On both dirt sides of the Abercrombie, you could easily sit on 100kmh without any issues. Well, you could back then, I have no reason to think the maintenance of this section would be any less now than then, it is reasonably well-used.
Any of the roads around Oberon/Hartley/Tarana/Jenolan Caves are just nirvana - except in school holidays
5. The stretch from Taralga to Goulburn is fairly boring, watch out for speed cameras anywhere within a 15-20km radius of Goulburn.
Sorry for the long post, I really enjoyed the trips up to the Rage.
regards
LeylandBrothersDave