Cars can be hired at Alice Springs or Darwin. It is possible to hire at one and drop off at the other, but probably best to check with the company beforehand. Tennant Creek is North along the Stuart Highway from Alice Springs and due south from Darwin & Kathrine.
There are several bus services that pass through Tennant Creek 
The Ghan, the running on the famous Adelaide-Darwin route passes by Tennant Creek twice each way per week. Tennant Creek may not be a scheduled stopping point and so prior investigation when booking is advised.
The town itself is relatively small and thus everything within the town can be reached by foot. A car is neede to reach attractions slighly further afield.
The Bill Allen Lookout offers a clear 360-degree view across the landscape and town - it's especially worthwhile to do this at sundown.
Tourist attractions can be found near to Tennant Creek . They cover areas like the town/region' history, aboriginal art and areas of natural beuaty.
There are several small shops including a supermarket in Tennant Creek mainly selling the essentials.
There are several bars/pubs as well as a liquor store.
The Eldorado Motor Inn  is comfortable, clean and feels relatively safe.