Ten thousand years ago this was a green country with giraffes, cattle and swimming people, and somebody painted all of it on the walls of the Tassili n'Ajjer. The plateau covers more than 72,000 km2 of sandstone, got UNESCO status in 1982, and holds one of the largest groups of prehistoric rock art in the world. Djanet is the oasis on its south-western edge, a town of roughly 10,000 to 15,000 people depending on the count, mostly Kel Ajjer Tuareg, built around three old stone villages (ksour) on either side of a dry riverbed, the Oued Idjeriou. It has been its own province only since 2019.
Be clear about what this trip is. You cannot wander into the Algerian Sahara with a rental car and a map. The south works through licensed agencies, a guide is required in the park, and the visa on arrival for tourists is tied to a booked tour. That is less of a hurdle than it sounds: the agency does the paperwork, feeds you, carries your bags on donkeys and drives the 4x4. Five days is a taster, not the full thing. Serious Tassili treks run 4 to 7 days on foot, and the Tadrart Rouge alone is a week in most itineraries, so this plan picks the best short version of each and is honest about where it squeezes.
Day one is Djanet itself, the old villages and the first dunes. Days two and three go up onto the plateau on foot, with donkeys, for the Tassili cypresses and the rock art of Tamrit, with Sefar as a stretch goal that depends on your agency and your legs. Days four and five are the long 4x4 run into the Tadrart Rouge, to the Tin Merzouga dunes, the arches of Tamezguida and Moul N'Aga; with roughly six hours of driving each way, about half of those two days is spent in the vehicle. The season is October to April; in summer it is far too hot to walk. Start on a Sunday, Monday, Tuesday or Wednesday, because Algeria's weekend is Friday and Saturday and you want the first day, with the museum, the market and any paperwork, to land on a working day. More about the country is on the Algeria page, and the capital end of the trip is in 5 Days in Algiers.