I was looking at doing a run (before I realised I had completely overlooked an upcoming overseas trip that will give me enough SP) and it seemed pretty clear to me the best option is some kind of regional route going via a main centre. E.g. in Chch doing something like Chch to Kerikeri via Auckland and home again is doable in one day as I do this day trip for work 3-4x per year - provided the outbound or return Kerikeri flight isn't cancelled, which literally was me the other day - and seems to yield at a better rate than anything international.

Hardly the most glamorous travel, but very manageable.