I found what needed to be done. On this post how to call latexmk, I just had to add the
(add-hook 'LaTeX-mode-hook (lambda ()
(push
'("Latexmk" "latexmk -pdf %s" TeX-run-TeX nil t
:help "Run Latexmk on file")
Tex-command-list)))
Now, I am just left with having okular to produce the pdf after completion. Does anyone have an idea on that?