Sorry, but you've lost me there?

If you mean to say I'm not listening, I assure you I most certainly am, and I'm revising my route accordingly. I just still have a few more things I'd like to know, simply to keep my options open.

Maximum speed limit on normal roads is 100kph, typical speeds are 70-80kph on straight roads, sometimes as low as 30-60kph on mountain roads.

Yes, you can ride 500km in a day if you keep to the motorways (120kph speed limit) on the flat coastal plains. You could cross over from Spain, hop onto the coastal motorway, ride down past Casablanca, and carry on riding the motorway to Marrakech. Have an evening in Marrakech, next day ride over the High Atlas mountains, then past Telouet Kasbah and Ait Benhaddou ksar to Ouarzazate (4-5 hours). Bikershome is a good place to stop. Have a day in the semi-arid area around Ouarzazate, a second night at Bikershome, then ride to Casablanca, and on the final day all the way back again to Spain.

Great, thanks for the advice Tim, much appreciated bier