Totally agree the four season bag is good for about -15c and has so far lasted for two longish treks.

Your itinerary looks great.

For the Day 3: Desert/Oasis tour around Tozeur, I would recommend spending the morning to visit Tamerza, Chebika and Mides canyons by 4x4 and then go to Douz and spend the night a desert camp, the next day you can go to Eljem by louage from Douz.

have a great trip.

Well you could do Death Valley and Joshua Tree with a few other places thrown in........
2 Nights Death Valley
1 N - Palm Springs via Searles Valley, in the morning take the tram up to San Jacinto, great views then over to Twentynine Palms for a couple nights. Go via Cottonwood Springs, south entrance to the park.
2 N - Twentynine Palms for Joshua Tree, beautiful place, nice sunsets and good star gazing.
Back to Las Vegas via a drive through in Mojave National Preserve, go via Cima. It's a scenic remote drive, outstanding country in the winter.
No worries about snow, very nice desert trip........Days should be sunny and warmish, nights will be chilly/cold.

https://goo.gl/maps/L2NtzyEimoE2

I did it myself. And I'm a notorious cheapskate, so you can bet it didn't cost me very much. Actually I started my trip in Casablanca (airport) and visited Casablanca; Rabat; Meknes; before arriving at Fez (I visited Marrakech nearer the end of my trip, before proceeding to Essaouira; El Jadida; and finally Casablanca (airport).

I can't advise on any nice day trips or excursions out of Marrakesh, but a day hike is possible around the old Medina, however this happy situation will probably be spoiled by the presence of false guides, street hustlers and brat pack children offering (mis) guiding services in the area north of the Souks on the main square Djemma el Fna, so if determined to pursue this risky plan make sure you have some backup navigation system in place to find your own way around and ignore the brats who will deliberately point you in the wrong direction, even if you pay them in advance they will direct you into the clutches of other small "mafia" brat guides, it's a well-organised system to extract money from the unwary tourist.

Fes iel Bali Medina s definitely a good base location to plan day excursions to the surrounding countryside and Meknes is less than one hour by train from Fes, but beware on the return journey of the latest scam I managed to dodge earlier this year, a big Fassi false guide bounced on to the train at Meknes station and made straight for the first class carriage where he imagined most tourists would be travelling, this ploy was to inveigle gullible foreigners into commission-generating hotel accommodations or fake guide services around the Medina, sadly two American women in the next compartment fell prey to his advances by politely engaging him in conversation, fortunately I managed to make my escape undetected before being subjected to a wallet-draining experience, I suspect the American women would not be so lucky.

If approached by polite strangers offering guide services or any other commodity it's essential to leave your good manners at home and totally ignore these greedy opportunists, bear in mind that false guides are illegal and if caught without a guide licence they will be arrested by plainclothes police.

...... the Chefchouen leg of your itinerary makes the road-trip too long, skip it. The journey to Chefchouen takes about four hours eachway, a slow mountain trip for not very much, El jadida would be a better and enroute to Casablanca use of your time. While you are in Meknes/Fez, a trip to Moulay Idriss and the Roman Ruins of Volubilis is easily done in a day. The 'Village Moulay Idriss' is the most sacred village in Morocco, this is where Islam took root in Morocco, where a fleeing prince from Mecca took refuge giving the village his name, and began the Arab/Islamic Conquest.

For Casablanca, this huge city is worth while visiting, the places of most interest to tourists are in close proximity, within walking distance for the most part, a City-Street-Tram system could be useful to hop-on-and-off as you go.

See this clip from Tahir Saha of The Guardian, a good templet for a day-long walking trip....
http://www.theguardian.com/travel/video/2010/sep/09/casablanca-insider-guide-tahir-shah

http://www.urbanrail.net/af/casa/casablanca.htm

"Saharan" people, you mean The Sahrawi, or Saharawi people - they are not living in North of Morocco but in Western Sahara, Algeria, Mauritanie. A very few are living in south Morocco.
But I reported your thread, it looks like you are marketing the travel agency and it violates the LP rules.
In addition, the company does not tell the truth, if you go with them to the desert, you go to Erg Chebbi or Chigaga but never to the "Great Sahara Desert" which is many miles away in Algeria or as said in Western Sahara.