If you only have time for a couple of stops in the East MacDonnell Ranges, make Trephina Gorge Nature Park (75km from Alice) one of them. The play between the pale sandy riverbeds, the red and purple gorge walls, the white tree trunks, the eucalyptus-green foliage and the blue sky is spectacular. Depending on the time of year, you'll also find deep swimming holes and abundant wildlife. There's a rangers station and campground with barbecues, water and toilets.
The Trephina Gorge Walk (one hour, 2km, marked with orange arrows) loops around the gorge's rim. The Ridgetop Walk (five hours, 9km one way, blue arrows) traverses the ridges from the gorge to John Hayes Rockhole; the 8km return along the road takes about two hours. Along the way, birders will want to watch for the yellow-throated miner, dusky grasswren and even budgerigars. Other hiking possibilities include the Panorama Walk (one hour, 2.5km, red arrows).
The delightful John Hayes Rockhole, 9km from the Trephina Gorge turn-off (the last 4km is high-clearance 4WD only), has three basic campsites. From here, the gorgeous Chain of Ponds walk (1½ hours, 4km loop) leads past rock pools and up to a lookout above the gorge.
Note that a couple of elderly tourists died after getting lost while hiking here in February 2017, after a sign was washed away by heavy rain – always stick to marked trails, and carry sufficient water at all times.
The road in off the Ross Hwy is sealed for the first 3.5km, then turns to gravel, with some (usually shallow) water crossings to the gorge car park. On your way to the gorge, take the turn-off signed 'Ghost Gum'. Just 300m off the main track, you'll find what is believed to be Australia's largest ghost gum, which may be 300 years old and hence predates European settlement in Australia. It's a magnificent specimen.