I think you can swing it. After all, all you have to do is head for the popular Tassili-Hoggar (Tagrera) region SW of Tam via Tirinine, Tadant, Tin Tarabine - it's a regular tourist route - just follow the toilet paper trail (it's not in the big book but the one desribed in Desert Travels) done in the late 80s - and then head SSE to IGZ (via the early part of A14 if you like) until you pick up the Tam-IGZ piste/road. We did this ('officially closed') 'Tarabine Tadant Tirinine [TTT]' route last month and hope to be going back the other way to Tam next month (mostly following A14 - much wilder than the TTT route).
It may help to clarify that as I understand it the restricting factor is the Wilaya of Illizi (the 'county' which includes In Amenas oil fields, Djanet Nat Park but not IGZ or Tam). They say 'no' to just about everything that is asked for, access/permit wise. Coming back from Djanet our local guides dreaded even leaving the road too far for lunch or driving late for fear of getting in trouble with the militaires (these guys weren't exactly the pick of the crop, it has to be said). You/your guide tell Izi wilaya you are heading for Tam as normal, but once out of Illizi wilaya, Tam wilaya to the west is more slack (I am told) and you head direct for IGZ, with guide's approval/understanding of course. Some guides/agencies are more 'up for it' than others. Then again this whole 'Tam good - Izi bad' thing could be just regional bigotry and used as a way of staying safely on the 'tramlines'. One's b/s filtration machinery can get pretty worn down out there after a while.
As for the kms, who can know on an unknown and irregular route like this - its depends on which way you go, no? In these cases one just estimates the distance on a map and with a ruler and then adds in a factor of error? That's how I and I'm sure most people plan all unknown/new routes.
(Edited for clarity 22.22)
Last edited by Chris Scott; 9 Jan 2007 at 22:22.