Algeria - Backpacking solo

[giugo]

I'll be in Tunisia in early March this year, and hope to visit Algeria as well. However I'm not sure which way is better, cost-wise: fly to Algiers from Tunis (160 euros rtn) or cross one of the borders.

Is it possible to take the bus/train (local transport) to the border, as the Lonely Planet Africa on a Shoestring (2004) says, or do I have to travel on a car, which would involve lots of hitchhiking? And, at present, is hiring a guide mandatory, regardless of whether I fly to Algiers or cross the border, and will I be 'forced' to hire the guide for the entire stay in Algeria (2 weeks +)?

Sorry for so many queries, but I couldn't find direct and up-to-date answers after searching through this and other Web sites for the past 2 hours.