If you're already got a ptz watching the driveway, then I'd be inclined to do what Hobs suggested and mount it on a post looking back towards the house. One of the issues of pointing cameras away from a property is people close up can walk under the cameras vertical field of view and anything they do then is uncaptured. They can alos come from the side outside of the horizontal field of view and walk under vertical all un-captured. Further, if you mount the camera on the garage, you'll never get evidence of anyone breaking in because they're outside the field of view when hard up against the buidlings. When you point a camera backtowards a building there are 2 advantages: 1 the field of view both horizontal and vertical becomes wider the closer to the building and further away from the camera you go. 2. You capture anything done to the building such as the act of breaking in. The only real way you can do this if you mount on the building pointing away, is to point cameras horizontally across the front and use multiple cameras and "cross them". So far as a post is concerned, you could put anything there and disguise it - a statue, ornament, build table etc.
My neighbours think I'm crazy having my back yard camera pointing back towards my house. But with their camera, it sees whats down the garden but can't see anything coming from the side or underneath the camera so will miss any actual break in only capturing people on approach and not if from the side leaving major blind spots. By contrast, my camera captures the whole house from floor to ridge line and it's entire width. The one thing people worry about is someone sneeking up to your camera un-noticed and taking it out. However, as you have a ptz looking out, this can't happen and it's very rare cameras are ever attacked. In fact most of the time they go un-noticed until too late anyway by Joe Average whoe's the opportunist or amateur thief. In a large property you might attarct someone more professional but as said you have ptz cover looking out so I wouldn't be concerned.
