Firstly, enlightenment is not the fruit of a painful path. Enlightenment is the fruit of a path of non-sensual pleasure, i.e., meditative concentration, calm & bliss. This path of non-sensual pleasure is called 'The Middle Way' (SN 56.11).
Also, to go with the flow is both not a joyous ride & not related to any type of Buddhism.
As for freewill, it does not exist in Buddhism. Buddhism teaches the will is dependent upon ignorance, or otherwise, wisdom. For example, AN 9.7 says it is impossible for an Arahant (Fully Enlightened) to perform certain types of unwholesome actions. Therefore, an Arahant does not have freewill.