First, are you sure you can get a visa/into Algeria without having an escort meet you at the border?
If anything regs have got tighter in the last month or two in Algeria, possibly following unconfirmed events.
The invite/escort and planned route will all be related: ie, they will only approve a safe route for you.
Then, as you say Kabilie is the least safe corner or Algeria - frequent ambushes, etc.
Also, according to this post:
http://www.horizonsunlimited.com/hub...2-7#post285048
the army are supposedly about to make a move after many years.
So, the safe route is the one they allow you to follow, if they let you in at all.
Before you book Tunis ferry be sure you can get into Alg, or book a return and get a refund if you dont use it.
Ch