I think one of the biggest adjustments will be going from a flat bar to a road bike is the braking. In my case I find I just cannot adjust to the large levers and it hasn't helped that I cannot pull the brakes very well. I have put extra lever on the top of my handlebars on my road bike and I only use them. I just don't feel safe without being able to get at least 2 fingers around the lever.

So make sure you are happy with the road bike bars, otherwise if you haven't got them already, bar ends add extra handholds to a flat bar. Also NZ is mainly chip seal. A carbon fork is a great addition, however a carbon frame is give or take (there's no great difference). Also weight of bike is a big thing. Some AL bikes are the same weight as a carbon. However my AL bike was around the 16kg mark and my carbon the 10kg. I gained 6km/hr speed wise on the carbon (I wasn't such a bad rider after all)!