VSCC

"If there is something you had to upload directly to a folder, not through WordPress you won't be able to unless you have a paid account. "
Not sure where this is coming from. Having a Pro account doesn't have anything to do with folders or uploading anything at all (nor does a free account). Are you talking about doing something via ftp?
You should either FTP to your server's IP (ftp://yourserverip/)
address or to:

direct.yourdomain.com

Exactly, Cloudflare has no effect on your original hosting servers IP address just get the IP address of the hosting server before you switch over, you can easily find it by doing a A record DNS lookup on your existing domain, you can use a simple online tool like http://www.mxlookups.com or similar.

Cloudflare doesn’t give direct access to your site but rather proxies this in a manor. So once your name server records have changed your original domain will no longer point at the hosts IP but to one of cloudflare’s.

During the initial setup a DNS record of direct.yourdomain.com is created. this by default is the only name server record pointing directly to the originals hosts ip. So unless you changed it on setup anyone can bypass the cloudflare service using http://direct.cloudflare.com. So I always remove it, but you could also use this for ftp connection if you still have it.

A bigger concern to me is any potential effect this may have on Google ads? as the originating ips of visitors become those of cloudflare’s, does this have a detrimental effect?

I’m in the process of searching for a answer now. I also have a phpbb site that I use cloudflare on and I read on there support pages a recommended change to the session.php file to allow original IP pass through. I wondering if wordpress has any issue at all, found this thread while searching thought I would reply, so for posting on 3 week old thread.