Chris Scott provides Matthew Traver with some good advice on travelling the Sahara.
Matthew Traver » ExplorerWeb »
Mauritania: Good security for at least 400km east, inland from the Atlantic Coast. Provinces near the Mali border, such as Adrar, Tagant, Hodh El Gharbi and Hodh Ech Chargui, may be less safe.
Western Sahara: Travel and access along the N1 Atlantic Route, running down the Atlantic Coast, is easy and safe. Expect a few military checkpoints.
Tunisia: Avoid the Libyan border zones and the far south, which is a military area.