So the SQL Reporting Services Service Application is running, but from Central Administration, when I click on the service, then click "System Settings", it returns an error.
Digging through correlation IDs, I found that the Web Service was returning:
HTTP Error 500.19 - Internal Server Error The requested page cannot be accessed because the related configuration data for the page is invalid.
Error Code: 0x80070003
Config Error: Cannot read configuration file
Config File: \?\C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\WebServices\Reporting\web.config
I go to the directory to check permissions on the folder, only to find it doesn't exist, though I've also confirmed in IIS that the virtual directory application is pointed there.
I've uninstalled and reinstalled the SSRS SharePoint Add-In from the SQL disc to no avail.
Additional Details Windows 2012 Datacenter, SQL 2012 Enterprise SP1, SharePoint 2013 Enterprise