There is no free WiFi in the parks. There is WiFi but it is only for the CM's which is password protected. The only way to get free WiFi is by heading on over to the DLR hotels which you can get the WiFi.
Sometimes you can get Wifi in the queue for Pirates of the Caribbean as well (if it is turned on for the dream suite.) I wouldnt be suprised if wifi being installed at DLR is the first step in getting the resort started on the MDE path.
WDW has had free wifi in all the parks for a few years now (for sure since 2012, when I last went there.) It wasn't bad then, and I've heard it's gotten better in more recent years. I'm actually surprised they haven't started integrating it at DLR, though the congestion of people may be a factor.
Thanks for all the replies. Now I know that there is no reason to take my cell phone into the parks. I was going to use it for wait times but it's too expensive on my cell plan to be looking at it all day long, and was hoping for wifi.