One of my favourites is a round trip day ride from Canberra to Bega via Batemans Bay, Moruya and Narooma. that leg is about 3.5 hours and around 270 km. The return trip is from Bega to Canberra via Cooma, that leg is about 3 hours and 250 km. That ride gives a good mix of everything, a mountain descent down the Clyde mountain and a mountain ascent up the Brown mountain. you also get a mix of coastal riding and some high country plains. Just beware that around Nimmitabel it can get bloody cold even in summer. I usually find coppers lurking at Batemans Bay, Narooma, Bega, Cooma and Bredbo. Hope this helps Cheers
PS: It's just as much fun to go the other way around as well.