I have a common little snippet I drop at the top of a lot of projects, to set use lookup paths relative to the running binary.

my $rundir;
BEGIN { use File::Basename; $rundir = dirname($0); }
use lib "$rundir/lib";
[download]

Then you can have

/any/old/random/place/script.pl
/any/old/random/place/lib/Foo.pm
[download]

and just use Foo, relocating the whole project at will. Obviously not perfect against the case of you running the script via alternate hardlinks or such, but...