I'm currently running ONLY the forum software and its under the /forum subdirectory of my site. I have the forum subdomain (forum.blahblah.com) pointed to the forum subdirectory so thats the direct link to the forum.

I want to change hosts and upgrade to the CMS suite...but I'd like for the www subdomain to point directly to the CMS page...Do I need to install the suite in the root of my server and do some trickery?

What kinds of issues will I run into when I change hosts AND change folder structure on the transfer...should I change folder structure? Any suggestions on what I'm trying to accomplish?

I will not be upgrading to the CMS until AFTER the transfer, so when I'm done transferring I want to already have my folder structure in the optimal configuration for the site to function...and still not be too confusing if I host some other subdomains off the root of the site.