OK .. I ll go .
(Assuming you are a EU national ) You need visas for Mauritanie , and Mali only .
You can get Mauri visa at Casablanca 3h, or at the border .
You can get Mali visa at Nouathchokk 2-3h
If you get a green card @ home , then that's valid in Morocco . If not , you can buy insurence in the border @ Ceuta. In mauriania you must buy local insurance (Nouadhdibou or at the border) . Insurance for Mali and SEnegal is the same .. and can be bought at either border.
MOROCCO is ok as long as you have a grey card.
MAURITANIA is ok .., they write the vehicle's detail in your passport , so you can not leave the country without it .
MALI , ok .. Local "passavant" issued at the border , they dont write details in passport ,
SENEGAL (If entered from Mali , apparently ) issue local "passavant" , and -depending on the officer- write or not vehicle details in the passport. (Note that in the north border there are restrictions to vehicles older than 5 y.o. , but not in the border with Mali.)
Shipping vehicle back to EU seems to be easier from Gambia ( www.pabloshipping.com
) than in Senegal , as Gambia dont write any vehicle details in the passport , hence-is possible to leave country without the vehicle. Also , there are some really cheap flights out of gambia.
Route is definitely doable in most vehicles , and should take a absolute minimum of -say- 10 days .
Depending on the mood of the officers , you may be required to show a yellow fever vacitination certificate.For Senegal & Gambia should take some sort of anti-malarial protection.
Enjoy your trip..