Scenic Southern - 2nd half of July - any tips?

Hi all,

I'm planning to head to NZ for 2 weeks around mid July. I want to spend 3 days in Auckland and 3 in Wellington (job hunting) and then join the scenic southern.

Worth joining at Wellington and sailing to south island or just fly to Christchurch and start the tour there?

I see the tour has 2 days in Queenstown, is it easy to get some snowboarding in on those 2 days? (never been to NZ before)

I know 2nd half of July is the heart of winter in NZ, anyone done the southern scenic at that time of year before? I know it will be cold but will the majority of the tourist type activities still be open?

Grateful for any hints/tips/thoughts.

Thanks :-)