We thoroughly enjoyed staying at Imogen's place for two nights - before and after the Tongariro Alpine Crossing.
There are plenty of room outside for off-street parking and kids to play (we were three adults and five kids). There are nice new decks in front and back of the house. The hot tub was very popular especially after the Crossing.
It is very warm inside even at night time when temperature drops quite a lot in that area (having said that, we stayed in March which is NZ autumn). The kitchen was well equipped, which was very helpful for a family like us. The house has been very nicely renovated/redecorated.
We were max number for the place to stay (eight of us), and it was a little bit tight fit to be honest even though five of us were kids (9-12 years old). We didn't mind at all, as this was a family trip, but for a trip with friends, you might want to plan your sleeping arrangement in advance.
Overall we really appreciate the kindness of Imogen to offer such a lovely place, and we would definitely recommend anyone who intends to stay in the National Park area.