This is an excellent alternative to the main road south. It travels through a largely empty highway along the alpine foothills through valleys and across rivers. Its relative isolation and lack of traffic makes it a very attractive route. Yes, it is slightly hillier and longer; it misses the lovely sea road from Kaikōura to Goose Bay and the views over the Canterbury Plains as you head to Cheviot; and on leaving Kaikōura you will not see a store or pub or accommodation before Mt. Lyford. But it is beautiful and mercifully free from highway traffic.
Kaikōura to Christchurch
Kaikōura is a small, lively town with a number of good cafés, restaurants, campgrounds, Youth Hostel and backpackers. The setting is magnificent with great mountains in the background and a startlingly blue/green seafront. Kaikōura has an opportunity to swim with the dolphins or book a whale watching trip.
Once you leave Kaikōura heading south, you will enjoy a flat, rocky coastline for 20 km until the road curves inland and up the Hunderlees, a range of hills that rise and fall for forty or so kilometres before rolling into Cheviot. Much of the road is broad and sweeping with great views of the landscape and a number of small and dying towns between.
Cheviot is a good place to stay. It is a small, pleasant service town with a supermarket for supplies and a friendly camping ground. Alternately, you might like to stay at Gore Bay, approximately eight or so kilometres east on the coast.
From Cheviot begins more rolling hills (38 Km or so) followed by a downhill run of around 76 Km into Christchurch. (There is a campground, store and pub at Greta Valley, approximately 32 kilometres out from Cheviot, a pretty place). Although a main road, the cycling is generally relaxed and the fields, plains and mountains provide broad and picturesque views. There are a number of longer, quieter side routes open to you. Try the inland state highway 72 (check your map for this). Highway 72 is a beautiful, quiet and welcome change to the usual main south road (turn inland at Amberley and you can miss Christchurch altogether). By now you will have experienced some of the joys of South island cycling.
The long bridges that cross rivers coming from the Alps run swiftly down over light grey river stones to the sea. Bridges of course are notorious places for cyclists (few drivers appreciate either your slower pace or lack of space). Nonetheless, these broad, clear, blue and green alpine waterways are magnificent.