Passports of every member of the family – each person should have their own passports, you can not have your child on your passport anymore. If you are married the passport should be in your married surname. Definitely take your drivers license with.
Take copi.jpges of all your documents along: passport, vehicle registration, etc. – certified of course. This is in case something happens to the original, then at least you can get out of the foreign country.
Many African countries require vaccinations/immunisation. Enquire about these before you leave. It would be a shame if you were denied entry in a country just because you didn’t know about the immunisations you should have gotten.
Travel insurance is extremely important. Make sure that your current insurance will cover you in the foreign country you are visiting. Also ensure the contents of your vehicle.
Make a list of all the important telephone numbers as well as a list of all the equipment (like camera, gps, etc) you are taking along. (Model, serial number) These lists of yours could prove to be very valuable in case of theft.