Traveling in a tour is a big no no. Not only do these tour guides help to prepare everything up for you, they also dictate as to your itinerary and ultimately, your whole trip. Furthermore, they tend to cost more because you pay for the salaries of these tour guides as well when you pay for your trip.
I say go by yourself. Do a bit of homework online before going. And by "homework" I am referring to knowledge like the schedules and fees of public transportation, some idea as to the price of goods, foods or other services, etc. You'll save a lot of money.
Last but not least, Oreki Houtarou from Hyouka noted that it would be more dignified to travel alone.