Lucy's new job paid twice as much as she had made working in

是状语。状语是修饰动词、形容词或者句子的。在这句里,分词短语working in the restaurant修饰句子she had made。相当于一个时间状语从句when she worked in the restaurant。定语是修饰名词的。在这句里如果硬要理解成定语,那这个“定语”只能修饰离它最近的名词性成分——代词she,能不能离这么远修饰姑且不说,修饰出来的意思也不合逻辑（“在餐馆工作的她”,好像有不只一个“她”需要界定）。