Scenic eroded cliffs, packs of Gelada Baboons, herds of endangered Walla Ibex, and home to Ethiopia's highest peak Ras Dashen (Dajen), the Simien Mountians are Ethiopia's premier trekking destination. While there is a fair amount of bureaucratic red tape, compared to many other trekking destinations in Africa the Simien Mountians can be trekked fairly inexpensively if done independently. Mandatory scouts are required to accompany foreigners at a rate of $5 a day as well as an entry fee and camping fee which comes to about $7 a day. So realistically you could trek for under $20 a day, though this involves carrying your own gear which is tough given the altitude.
Do It Yourself Information
Tent or no tent: I brought a tent but in retrospect I think you could get by without one. Gich there is a lodge that chages 80 Bir a night. Don't know what the one at Sankabar charges. And Chenek I'm relying on others info. Its all basic of course. Though if you have a tent one its probably better to have one.
Water: I would say bring capacity for at least 3 liters and a way to treat water. Most of the time 2 is sufficient but it does get hot and on the hike from Gich to Sankabar there is a long climb and no water. At Sankabar and Gich there is spring water at Chenek there is a pump well. At Ambiwa you need to get it from the stream. Going over Bawahit pass there is no water for the climb and only after about an hour of decent (from a stream). There were numerous reasonably clear streams to get water from on the hike to Ras Dejen.
Ras Dejen or no Ras Dejen: To tell you the truth I'm not sure if Ras Dejen is worth it. I think the vies from Gich to Chenek and at Chenek are better. It did have a dusting of snow on the peak when I was there so that was kind cool. Its a long boring trek through the valley to get there and even longer if you have to walk back the same way. I paid a truck driver to break the rules and give me and my scout a ride back. More on the transport mafia next.
Transportation: Unfortunately it appears park officials and the tourist transport lobby have conspired to make it technically illegal to use public transportation or trucks in the park. So they can charge rates that are higher than a New York City cab with an airport surcharge. People were being quoted like 3000 bir for a drop and pick up totaling no more than 30-40 km. So the only other option is walk or to pay the public transportation or truck drivers to break the law which means you will pay a lot more than the locals. To get back from Ras Dejen I had to pay a truck driver 400 bir and hide under blankets when ever we passed park check points. But it saved 3 days of walking and more importantly dragging my pack back over the 4200 m pass in the baking sun. When I was hiking in the bus offered me a spot for 100 bir to the first camp but I ended up walking it even though its a pretty boring hike. Ideally a good route would be catch a ride to Sankabar hike to Gich. Next day hike to Chenek. Stay two nights in Chenek and hike up to the pass on the free day or the peak behind Chenek. Then get a ride back.