\documentclass{article}

\usepackage{etoolbox}

\newcounter{listcount}

\newcommand{\ppath}[2][$\;\triangleright\;$]{%
  \setcounter{listcount}{0}% Restart list count
  \renewcommand*{\do}[1]{\stepcounter{listcount}}% Count list item
  \docsvlist{#2}% Process list and count items
  \def\nextitem{\def\nextitem{#1}}% Separator
  \renewcommand*{\do}[1]{%
    \addtocounter{listcount}{-1}%
    \ifnum\value{listcount}=0 ~and~\else\nextitem\fi\textsf{##1}}% How to process each item
  \docsvlist{#2}% Process list
}

\begin{document}

A decent file path is \ppath[, ]{File,New,Document}.

\end{document}