Our trip to New Zealand is in final planning stages now! All flights and city accommodation booked, hire car arranged for North Island but would appreciate some input re South Island. We will be arriving in Christchurch from Wellington via ferry and Coastal Pacific railway 16th March 2014. We fly out of Christchurch 6.30am on 28th March. We will be picking up a hire car for the first part of our time in S.I. but are thinking of doing a short coach trip (so the designated driver gets to see something other than the road!!) to Milford Sound, Mt Cook, Doubtful Sound, Queenstown from Christchurch 23rd March returning to Christchurch on 27th with airport transfer on the 28th.Will we have enough time to self drive some or all of the Southern Scenic route, Caitlins etc in the days prior to the coach trip?