I'm heading to Wellington with my girlfriend from 25-29 June and thought the Tongariro Alpine Crossing looks like a decent side trip. Is going with one of the guided groups is a must, as opposed to hiking it by ourself? I've got experience hiking in snow but with snowshoes, never with crampons/ice axe.
I didn't end up doing the crossing as the weather wasn't in my favour, but I met someone who did the crossing a few days prior. They had no problems, no need for crampons, there was very little snow.