A good dog can be a good ounce of prevention - and a well-trained good dog can be a friendly 24/7 security guard. Anecdotal: I know of a local country store where a man some years ago came in and attempted an armed robbery. He didn't pay enough attention to the store owner's well-trained shepherd that was laying quietly on the floor behind the counter. The bad guy blinked...and in the blink of an eye he lost his gun and needed about 150 stitches. My dogs are well-trained and they have better instincts/reflexes than I do in a crisis.
Dogs, Cell Phones, access to a firearm - can all work well. Plan of escape?
The best laid plans can fall to ruin. It's good to keep options open - and not have a 'plan' that is too tight or confining. Cell Phones are wonderful. I don't have children in the house or children that visit...so I can afford to keep a few things stashed in places<including cell phones>that might come in handy. It's nothing interfering with one's lifestyle...but there's no area of the house where I would feel 'trapped.'
Surveillance systems are great too. In fact, I'd say 'prevention' is key. Escape plans are okay, but one gets more bang for the buck with $ and time spent on prevention. If someone breaks in while I'm in the house asleep - the first prevention is to have something that will will make sure I'm alerted in time to the break-in. Makes no sense to have an escape plan, if I won't even know if somebody has broken in and invaded. If somebody is on top of me, then any escape plan sorta flies out the window. My Home is My Castle and the Castle Doctrine applies...
I wouldn't mind having a good moat.