There are three ways to get to Imilchil, all are hard. The one from the south is described in the Tineghir section.
The one from Fes, goes through Midelt and Rich. From Rich there is a piste P3443 by way of Outerbate and Sountat a wonderful trip, doable in summer in a Renault 4. Also Truck rides available. Two hotels in Rich, the Salama an al-Massira, both cheap and basic. Latter is better.
From the North last big town on paved road is Kasba Tadla, between Khenifra and Beni Mellal. The paved road takes you up to Cherket. From there its hard, but rewarding work. Aghbal, just of the Kasba Tadla Imilchil road is a place to spend the night.