One doesn't have to be very experienced or courageous to travel Namibia on one's own. The roads are good and there are good hotels, guest farms and lodges everywhere. The people are friendly and helpful, and communication should also not be of concern, because most Namibians speak English and German.
One can rent a car from home, conveniently through the Internet. Also, fully equipped 4x4's with roof-tent and camping equipment or compact caravans are available. Some tour operators also provide hotel vouchers and route descriptions for a self-drive-tour.