You can catch a Wainuiomata bus to Homedale and head into the Orongaorogas from there... not too far to walk from bus to green stuff

You can catch a train to Upper hut then taxi or hitch hike to Kaitoki road end.  For your intrest on bush ball we used co-op shuttles and with 11 people per shuttle it was $10 per person one way from uni to road end

You can catch the Wairarapa train to 'Woodside station' walk 4km up the road and head into the hills via Reevs

OR

Charlie Brown is also looking at doing something and he has a car