Help choosing some hikes....

Hi all, found this wonderful website. It seems so very helpful, I hope you all can give me some guidance and help me choose. I know it all comes to down to whatever I'd prefer, but NZ hikes are so wonderful it is too hard to choose! Being a typical American, I have around 15 days to travel after arrive to Auckland. I have already spent 3 weeks in the south island before and did the Routeburn and some other small day hikes. I wanted to return and see the north island some and also do the Milford - however the Milford is all full for the days we are going. So - here is my problem. 1. We'd like to do the Tongorio (either circuit or crossing) and another hike or two depending on the timing. Is the crossing simply the best of the circuit or does the circuit give you a lot of great views you don't get on the crossing? 2. What other hike or two (depending on answer to 1.) should we do? We are considering the Heaphy and/or Ball's pass. Another board suggested the Q. Charlotte. Anyone on here care to comment on which is better? Thank you all for your help!