Have seen several distance and time calculators i.e.
http://www.accommodationz.co.nz/distances2.html<BR>http://www.aatravel.co.nz/<BR>http://www.travelplanner.co.nz/driving/smlcalc.html<BR><BR>Which will give us the most realistic indication of how long it takes to get to places in Feb allowing for road conditions and traffic
We need to have a rough idea of
Te anau to Dunedin
Dunedin to Christchurch
Christchurch to Picton
We are used to driving on the left and on narrow english roads

jacquir
1

neilm
aatravel will be good if it's run by the AA, and will have built in to its times reasonable time for toilet stops etc
2
cyberia
I would say allow an average 25 mph for driving, and more for any places you want to visit along the way. Traffic is usually not too bad that time of year, though going through some towns and suburbs can be slow. Get a good road map. I can't remember any speed cameras there, though there are some around Auckland.
Pro tip