The most appropriate one-word substitution for the given group of words "An act of traveling to a place along a way that is different from the usual or planned way" is "Detour."

Explanation of the options:

☀ Postscript: This term refers to an additional remark or information added at the end of a letter or document.

☀ Amendment: This term refers to a change or modification made to a document, law, or agreement.

☀ Detour: This term refers to a deviation or alternative route taken to reach a destination when the usual or planned route is unavailable or undesirable.

☀ Rectified: This term refers to the act of correcting or fixing something that is incorrect or flawed. It does not directly relate to traveling along a different route.