Path Length Checker is a free stand-alone app that allows you to specify a root directory, and it gives you back a list of all paths (i.e. files and directories) in that root directory and their lengths. It includes features such as pattern matching and min/max length constraints, as well as the ability to specify a string that should replace the root directory in the results brought back, allowing you to quickly see path lengths if you were to move the files/folders to another location.

See https://github.com/deadlydog/PathLengthChecker/ for details.

Link: Path Length Checker