I would prefer if the crew met me after the grand line. Preferably at an island that holds an endurance trial. It could have been a competition with multiple groups.

 I guess the crew's reason for participating is anticipation. Rumors and stories from previous islands convince them to participate as they wanted to see how difficult the trial truly was. 

 Things happen where other parties become dangerous to others and Feya can't complete the trial by herself. 

Trouble ensues and by the end, Feya joins the crew who helped her complete the trial.