(Great puzzlement ...)   I simply source-code installed the latest Perl into /usr/local, after setting up my system with a case-insensitive file system for other reasons.   Then, it is pretty much identical to any other scenario of “installing packages as a non-root user...”   I encountered absolutely no unusual issues installing Perl and/or various CPAN libraries onto “this particular Unix variant,” and never had to use elevated privileges for anything.   I can’t imagine why you felt that you had to go to this much trouble.   (Of course, the system-provided Perl environment remained studiously untouched, once again “as is always standard practice.”)