Castle Torgeath Redux Release 1.3.2 includes automatic in-game switching between mouse and controller.

When you have both the mouse and a controller connected at the same time the game will initially assume you want to use the controller. You can automatically switch from controller to mouse by simply moving or clicking the mouse or pressing a key like Space, Enter, Alt, or Escape. To switch back to the controller just press one of the controller buttons, triggers, or bumpers.