htaccess redirect problem

I changed my blog today so that it loads out of /blog rather than the root of my domain. I left all the files in the root though and just configured WP to pull from there. Everything is working great, including the redirects to the new URLs.

The problem I’m having, is that I now need my root domain to forward to /forum without breaking any of the redirections going on for the old links.

This is the current code in my .htaccess file that is working.

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

Every thing I’ve tried to add to that to make the root forward to /forum, breaks the link forwarding from my old URL structure to the new one, post WP move.

For example, my old links looked like this:

http://backcountrypost.com/?p=1702

And my new links look like this:

http://backcountrypost.com/blog/vermilion-cliffs/coyote-buttes-north-january-2012/

That all goes off without a hitch until I do anything to forward request for backcountrypost.com to backcountrypost.com/forum. I’ve tried adding code to htaccess, which I’m not very familiar with and I have also tried creating a simple index.php redirect in the root. Either way breaks the old links from forwarding to the new links.

I’ve spent about 10 hours now trying to make this go. Please help!