Milford Sound Questions

Hi Richard, first of all, Congratulations on a fantastic site, excellent! wondering if you can help?? Hubby and I are off to Milford Sound for a hike in the next couple of weeks. We are wondering if anyone can compare the walk at all with maybe Mount Warning or Booyong walk- Border Ranges National Park in NSW. Elevation is our main query. Also , hot tips if you have any on good foot care during long walks. Thanks heaps Carina