I was able to accomplish this by simply setting up a page template to display for the forum using iframe.
I edited my page.php file, removing all of the code that calls and displays page content, and replacing it with the iframe statement. I left the div I used to enclose the text content in place, but changed the it's id to "forum," then added the id to my style.css file, with width=100% specified. I then removed the calls for sidebars, so the forum would span the entire content area of the page.
I also changed the width in the iframe style to 100%, so the iframe would span the whole text area as well.
It worked perfectly.
I wanted to keep the user registration separate, because the "blog" portion of the site is used managed as website, and doesn't allow comments and user registration, anyway.
So, with my setup, a page template that displays the forum using the iframe tag and a small addition to my style.css file were all that was needed. No plugin's of any kind required.