use Perl

I'm not sure if this is the kind of thing you're looking for, but the following pipeline uses only software available on the default OS X install

perldoc -Tn '/usr/bin/groff -S -mandoc' "$input_pod" | pstopdf -o "$output_pdf" -p -i

"Her Royal Highness" is applicable only to princesses and so would apply to Her Majesty, The Queen [as she is now] only when referring to her at a time prior to her accession, as in "Her Royal Highness, The Princess Elizabeth [as she was then]".