We went to Milford Sound from Christchurch via Queenstown. The bus service of Intercity is very good, friendly and punctual. However there are no bus service/train for night travel in New Zealand and that's a major disadvantage travelling on public transport there. Anyways Milford Sound is heaven on earth, the waterfalls jutting over the sea is higher than Niagara Falls. Must do cruise to view dolphins swimming and swims rest on rocks. Haven't seen such a view anywhere else. You can preorder Indian meals while booking the package through Intercity. Dont miss Milford Sound cruise when you are at New Zealand. Happy exploring!!!
By the way stoppages in New Zealand buses have ample clean rest rooms and good eateries so no worries about travelling by bus !!