"Come along" can be replaced with various synonyms depending on the context and tone of the sentence. Some synonyms for this phrase include "accompany," which implies a formal or polite request; "join in," which suggests a causal invitation; "tag along," which can indicate a more casual, friendly invitation; "follow," which can indicate a directional instruction; and "advance," which can indicate progress or movement towards something. Other synonyms that can be used include "proceed," "follow through," and "continue." All of these synonyms can be used interchangeably with "come along" to achieve the desired tone or meaning in a sentence.