August- September trip

I am going to be in NZ for about nine days in the end of August into the first week of September visiting my girlfriend who is studying in Lincoln. Just curious if anyone has any suggestions on some tramps (2-4 day) that would be better than others during this time of year. Not sure if we want to do a couple shorter trips or one long one. I know this is a pretty short trip and not the best time of year for tramping, but it is the only time I can make it to visit. Also, we are considering a sea kayaking trip. Is this possible this time of year, or would tramping be better? I am an experienced outdoorsman but my girlfriend is fairly new to all of this, so somewhere in the middle on the difficulty would probably be best. Thanks for any help!