cross the line vs go a long way

To achieve completion of something. 

To finish a race. 

To overstep a boundary, rule, or limit; to go too far or do something unacceptable. 

To cross the equator, as a vessel at sea. 

To film from the opposite side of an imaginary axis on set in order to view the actors from the opposite direction. 

To achieve considerable success. 

To be adequate or helpful for a significant amount of time.