Australia - New Zealand - 5 months New Zealand - which island first?

I'm planning to go cycle touring in New Zealand for 5-6 months, starting in the last week of November. I had already decided to start in Christchurch and tour the south island first, but now I read that the south island is much nicer in autumn. So I'm looking for first hand experiences: where would you start and why?

And one additional question: I heard that it might be very difficult to find affordable accomodation (campsites, hostels) during December and January. I don't really want to pre-book, since I want to be flexible. Is this a bad idea? Will it be difficult for one person on a bike to find somewhere to sleep? Are there areas that are particularly crowded and that I should avoid?

Any tips are greatly appreciated!

Luxlumis, I guess that the New Zealanders are off line at the moment due to the earthquake although there weren't too many of them around in the first place. The South Island is WAY south. On par with the lower reaches of Chile and further south than Tasmania so it is cool down there. Early autumn is the nicest time of year in Canberra which is cool for Australia's capitals so I can easily imagine that Autumn would be nice on the south island too. You still have some summer warmth but no strong winds. Spring is pretty windy in this part of the world so the weather can change quickly.

Late December/January is the major school/summer holiday season in New Zealand and Australia so yes its peak time for accommodation but I cant give you any first hand advise.

Anthony

North Island = Summer. South Island = Winter. Hands down the summer is far nicer up here in the north island. I live in a place called Napier on the east coast of the North Island. If you want stunning scenery go to the south island in winter. If you want nice beaches and hot weather come to the North Island.

Take the North Island through summer (you shouldn't have too much trouble with accomodation, unless you are in the peak tourist/holiday areas over the Christmas break ie - Bay of islands, coromandel, gisbourne, etc) and then the south island towards the end of summer and autumn. Parts of the south island would be too hot in summer (think low 30s, but in the direct sun it feels hotter than any 37 degree day i've had in Sydney) and the place is stunning in autumn. Come winter, its getting too cold.

Any updates on the trip? Hope the weather gets better for you!

What the others have said...summer: North of the north ie. Northland/Coromandel possibly Gisborne.. winter - south ie. Queenstown/Otago etc - any other way will be crap for you