My friends and I have used Marrakech-based
Loc2Roues many times and have been totally happy. Nourredine will lend you helmets if necessary, also has luggage options (but we always take a roll bag and rok straps). The F650GS twin would be a decent bike but the seat is uncomfortable. I've taken an AirHawk with me before; my friend bought a £2 pillow and strapped it to the seat.
The best biking roads are the mountains but obviously it will be chilly at over 2000m (between 0.5ºC and 1ºC temperature drop for every 100m higher than Marrakech which is at 450m).
A very pleasant lower-level and all-tarmac route might be to head out of Marrakech on the N8 to Fez then after 12km fork right onto the completely empty R210 and head for
Demnate and the Imi n'Ifri natural bridge. After descending and walking through to get rid of some of the Xmas excess, return to Demnate and head north then east toward Azilal. Before you get there, turn left to
Cascades d'Ouzoud where you could spend the night. Next day return to the Azilal road, carry on to Azilal and the Bin el Ouidane reservoir. Return to Marrakech using side roads where possible for maximum relaxation.
Another day or overnight trip could be to Imlil which is at 1700m (though you can go higher). From Marrakech head south on the R203 and about 300m past the Afriquia fuel station in Asni turn left for Imlil where there's lots of accommodation options. See posts #12-14
here for more info.
Plan B might be to hop on the CTM bus to Ouarzazate (best part of five hours over the Tichka pass) and stop with Peter at
BikersHome. Lots of good riding around there though more suited to offroading.
Plan C could be to explore the Anti Atlas and the coast around Sidi Ifni to Mirleft from Agadir, but Agadir would be a terrible base (IMHO) for the rest of the holiday. Edit: just read Fanum's more eloquent explanation about Agadir.
