Kings Canyon, 314km from Uluru, part of Watarrka National Park, and yes all on sealed roads these days. I first visited here in 1979, bush tracks & no national park then, but the steep climb up to Kings Canyon was there then!
Up the top, weathered sandstone buttressed domes, the "lost city" & the "garden of Eden" to see. 6km walk up, around the rim on both sides of the canyon and back is spectacular.