As of now (8:00 Tues morning CHC) the Lewis Pass route is open. (Nelson - Murchison - Springs Junction - Culverden - Christchurch)
http://www.stuff.co.nz/national/nz-e...on-established

An inland route (via Waiau) Christchurch to Kaikoura likely to be open in a week, or sooner.
The coastal road (SH1 State Highway 1) and coastal rail through Kaikoura will take months.

So Nelson - Murchison - Reefton - Greymouth - Haast - Wanaka - Queenstown (West Coast route)
Or via Canterbury:- Nelson - Murchison - Springs Junction - Culverden - Christchurch - Queenstown
The West Coast route is more scenic, over a few days
It will take longer to drive between place in NZ than you first think.

Helicopter's are now taking some people out of Kaikoura. ~2000 residents (many of whom will stay) and ~1000 visitors

Still a lot of shakes in Kaikoura & Wellington area
http://canterburyquakelive.co.nz/
http://wellingtonquakelive.co.nz/

Air travel is not effected.
The Cook Straight ferry's are not operating:- damage at both Wellington & Picton.