Ok...
I spent the whole day cruising the GOR and otways twisties and so on... the verdict is thus.
I'm not sure it's a good idea to take the cruise along it, reasons being someone will die. If we have another driver like shannon (I have no idea what his username is) trying to keep up with wrcvr4 or whatever, they'll kill themselves no ifs or buts about it.
The runs are 77km one side, 102km the other side. Flat out twisties, imagine black spur on steroids for that distance. Your average speed between corners is about 100-140kmh with corner speeds depending on yoru cars capabilities but generally no slower than 60kmh.
There are no motorbikes or caravans. Occasional truck or boat but plenty of short straights to get past them. Plenty of places to yield to faster drivers too.
All crests lead to a really really sharp corner. There are no advisory signs except on the six hairpins I found which are all 35kmh hairpins. All longish straights lead to REALLY sharp corners or hairpins.
If you want to do these roads I suggest NEW or near new -really- sticky tyres, preferably R compound as regular tyres will heat up way past their usefulness. Brand new brake pads and yeah... a really long attention span.
All in all, a few of the more experienced members and I all agree that the roads are possibly not the best idea. I'm happy to lead small groups on runs through however, just not 20+ cars.