Te Anau is a relaxing place to visit. Some people prefer it to Queenstown. The activities in the area a confined to the National park mainly. The key attractions are of course the two Fiords. Doubtful and Milford. Doubtful sound is pretty much a day trip, as you travel across lake Manapouri and then climb over the Alps to the Sound. Milford on the other hand can be visited by you driving yourself there and back. For a comparison of the options you can read this article, it may help with your choice. Milford and Doubtful Sounds New Zealand.

The other major attractions in ther Te Anau area are the walks. You can do these unguided or guided. Milford Track, Keppler track, and the Routeburn are the most widely know. A  good walk to do is the return walk to Key Summit. You can do this from The Divide . This being the central part of the Alps as you drive into Milford Sound. The walk is 1 1/2 hours return. Great views.

Being in the Alps there are lots of lakes and rivers. Camping grounds have been setup by the DOC in most of the popular fishing and holiday spots. A licience is required to fish NZ rivers and lakes.