We did that route by truck in 1995 (up from Tamanrasset to Oran and catching a ferry to Alicante), and no-one killed us!
Police etc. were very friendly and helpful. But we didn't stop along the way much. When we arrived in Oran, it was mid-morning, we spent several hours getting ferry info, negotiating, booking, paying, etc., then filled up with diesel, and were loaded onto the ferry by around 5pm, for departure at 10pm, AFAIR.
I really don't know how to usefully judge that kind of risk - statistics don't mean much when there are only a handful of travellers. But the advantage of very few travellers is that presumably the bad guys are not really lying in wait - you probably have to be pretty unlucky.
FWIW, we are planning to go back via Spain-Oran ferry in April, though we may still change our minds.
[This message has been edited by SandyM (edited 25 February 2003).]