When I booked this, it looked so fun and driving through scenic areas looked so appealing, but as someone else said you are on main roads!! One of which was so major I was quite worried we would get a bump, some drivers were quite aggresive. So the issues, handed a map of the route, that really was totally useless unless you stopped and wasted your tour time of 1 hour. The SatNav/GPS kept turning itself off - it was not fully charged and was not being charged during the trip. noise of the engine drowned out the verbal instructions, not useful. We are not the largest of people, but the seating felt cramped for two adults and the operation of the steering felt odd in some situations. Now we being from the UK did not want to incur silly phone charges to contact the operator, so we chose to curtail our journey. And when we finally arrived back and advised the issues with the GPS, we were just told, oh OK, thanks for visiting us. Not one sign of the quality service we usually get from our American cousins!!
I have given this a three as it could be fun for some, when we arrived a man and his son had just finished their trip and looked totally happy. We did see nuermous others out on the road (also a lot in San Fran). The decision to undertake is yours!!