In February 2014, Sazy Rock and I spent two wondrous days camel trekking and two fun nights camping in Berber tents in Erg Chebbi, Sahara Desert.
Transportation
We took an 10-hr overnight Supratours direct bus from Fes to Merzouga, a little desert hamlet that is the gateway to Erg Chebbi (one of two giant sand dunes located on the Moroccan side of the Sahara Desert). The bus left at 8:45pm (although original departure time was supposed to be 9pm). Bus was a typical "luxury" travel coach with reclining seats and a/c. We had seats just behind the driver and between the blaring radio and headlights from on-coming traffic, it was difficult to get any rest. In the middle of the night, there's a "lunch" break of 45 minutes. Even though it was 2am, the bus stop had an open restaurant and clean restrooms for use.

We arrived early around 5:00am, 2 hours ahead of schedule. Somehow, the owner of the auberge Le Petite Prince (the overnight camping/camel trekking outfit we hired) was aware of this fact and came out to collect us at the bus stop. If he hadn't come, we would have had no way to get in touch via phone (had no phone number nor access to a phone) or a way to find it on our own with an address!
Other tourists arrive at Merzouga via rental car or taxi service. For the length of the drive, it really is best to take the Supratours bus. It is economical, efficient, convenient and clean.