Transport in and out of Debark can be quit a challenge indeed. My advise: trust the guys from the hostels in Gonder who will arrange transport into the Simiens and search other travelers to share costs with.
Debark only has some basic shops, you will be able to shop for some food, snacks and Drinks., most camping gear is for rent here as well. There are only two "hotels" in Debark advisable for tourists. Ask around for transport out of Debark before you head furher into the Simiens. They will help you to reserve a spot on the passing jeaps or trucks...
It was fun and everybody was very helpfull. Don't expect luxury...
