I had a couple more questions / issues:
1) How can I get a button to show up in the portfolio excerpt? I want to add a button that says "visit the site" and links to an external page in another window.
2) In the portfolio page with one column, the slide controls aren't showing up when I have multiple images. How can I add the scroll controls to the portfolio page?
I tried adding to loop-portfolio.php on line 52:
echo '<div class="slidecontrolls" style="visibility:visible; opacity:1 ">';
Which worked, but the unclosed <div> tag causes issues with the footer.