That can be simplified a bit by enabling the sub-forum search option (&sc=1) since phpBB doesn't distinguish between forums and categories – so the forums listed on the index page are technically sub-forums of their categories. You can therefore include all the categories except for the "Community Connections" one and just include the relevant forums from that.
We don't change the forum set up too often (i.e. basically never) so it shouldn't be a huge problem. I'll see if there's a sexier way to do it... but that's a fairly good solution for the time being.
Code:
http://68kmla.org/forums/search.php?fid%5B%5D=1&fid%5B%5D=3&fid%5B%5D=4fid%5B%5D=23&fid%5B%5D=24&fid%5B%5D=25&fid%5B%5D=26&sc=1&search_id=newposts
Yeah, that link still points to the main search results. You have to use the URI that II2II posted or one that I gave above (save it as a bookmark) to get the results without the Lounge.