Last week I was having a chat with a friend about different styles of bike trips. John and I have done all types of bike tours, including structured group tours, partially pre-planned tours with a few friends, and trips on our own or with a few friends, where only the start/finish point is pre-planned, and the rest is done on the fly. Each type has its advantages and disadvantages.
On an organized trip with a large group, you may meet and ride with lots of new people as well as some old friends. You might also have the bad luck to find a PITA (pain in the a$$) among the group! Many organized trips include vehicle support to carry gear, as well as providing snacks and support throughout the day, allowing one to fly up mountain passes without carrying a lot of stuff on the bike. Organized trips also come with assurances that you will have a place to eat and sleep, at a known distance. They also typically include a well-scouted route and a good set of directions. Occasionally, though, the directions can leave you desiring more while the actual distance can leave you wishing for less! Disadvantages with a pre-planned route are that one can't really make big changes based on weather, or the discovery of an interesting road or a cool looking place to stay.