There is a choice here. If you are enjoying
Glen Helen so far and feel like stretching your legs, why not spend another night and take the day to climb the mighty peak of
Mt Sonder, the NT's fourth-highest mountain. Reaching its summit will give you unparalleled views of the
West MacDonnell Ranges. The climb (not a climb in the technical sense, more of a steady uphill walk) starts at nearby
Redbank Gorge, about 20km west of Glen Helen, from where you can access the trail, which takes about six hours return.
This walk is in fact the final section of the famed Larapinta Trail, something to tell your friends when you get back. The trail spans 223km from Alice Springs and can be done in 10 to 12 days. Also at Glen Helen, you can take a helicopter ride to get a bird's eye view of the trail and the ancient landscape across which it winds. If you choose this option, bear in mind you will need to drop one of the subsequent days in this itinerary.
Alternatively, take the day to get back to Alice Springs, visiting the best waterholes and gorges the West MacDonnells has to offer along the way. Start at Redbank Gorge where a short walk will bring you to sheer cliffs and a narrow gorge where you can swim in a picture postcard waterhole, and, if you dare, brave your way through a combination of swimming and climbing to explore the inner sanctum of the gorge. It is recommended you use a flotation device such as an air mattress when swimming through the gorge. The water is deep and cold.
When you have had enough, retrace your steps back toward Glen Helen. But don't take the turnoff. Instead, keep heading towards Alice until you hit the sign for Ormiston Gorge, a few short kilometres down the road. Ormiston is a great place to relax and spend some time, or take one of the many walks on offer. You can get details of the walks at the Ranger Station. The Ormiston Pound walk is among my favourites in Central Australia. It is easily accessible, and takes only a few hours.
The road back to Alice Springs is alive with turnoffs to secluded gorges, waterholes and points of interest including the Ochre Pits (once used by Aboriginal people to mine materials for paints), prehistoric Serpentine Gorge and awe-inspiring Ellery Creek Big Hole, where you'll want to go in for a swim. Be back in time for dinner at a restaurant of your choice in Alice Springs (see "Where the Locals Dine"). But don't return the hire car. You'll need it tomorrow.