Move forum to subdomain or to a folder?

[daimpa]

Hello,

I want to move my forum and disable the VB CMS to have Wordpress in the root. do you suggest to move the forum into a folder (mysite.com/forum/) or to a subdomain (forum.mysite.com)? The forum is quite big, 15k users and 400k+ messages.
To move the forum in a subdomain or in a folder, I just need to move all files and edit 1 URL in the admin panel of VB, right?

Further, as soon as I move the forum in a subdomain or in a folder, I'll put wordpress in the root of my domain. I was thinking to set manual redirects in the .htaccess in my root from every VB articles to every Wordpress new article (for e.g. Redirect 301 /content/articleTitle /2014/05/05/articleTitle - Is this 100% correct?). Is there anything I can do for VB Forum sections and topics, or the only solution is to do manual redirects for the most important and best indexed sections and topics?