If they are going to Tangiers, tell them to do it themselves (and maybe just hire a local guide if they would feel more comfortable). We did an organised day trip and it was pretty awful - really just got about 3hrs in Tangier.
Without a doubt you should book the Hurricain Hotel. Gorgeous little family run hotel with beautiful gardens and views over the strights of Gib. Food is to die for, try the steaks.
They have horses too which is a lovely way to see the area.
One of my favourute hotels anywhere.
Can't fail to be impressed buy the homely feel to the place.