The answer to this question is subjective. Either answer can be adequately defended, and neither answer is more correct than the other. Additionally, "radical" and "conservative" are subjective, relative terms. What is radical for one person might not be anything close to another person's definition of radical.
Personally, I feel that anytime a group of people decides to overthrow a governing entity by using violence against that ruling power, it is quite radical. I generally consider violence to be a last resort option. The normal, "conservative," and/or political strategies have failed, and the only remaining option is violence. That's a radical step because thousands of lives would have been spared had the revolution not turned violent. America might be a very different country or maybe not independent at all, but saving lives is an admirable goal.
On the other hand, I suppose that staying passive and letting the British government dish out legislation that didn't aggressively care for the colonies could be considered the radical option. The idea of getting slapped and turning the other cheek is quite a radical idea to many people, so fighting back is the conservative option.