Anyone who really wants in is going to get in regardless of the presence of surveillance or alarms. An issue noted with schools who have deployed surveillance (in some cases, $100k worth of high quality Axis IP cams) is that anyone committing a crime usually has either a hoodie on, or a bandana covering their face, making the footage pretty useless.
So, you'd be better off working the physical security aspect. A whopping great deadbolt would do it, 2 if you feel like it. All you wanna do is make a potential theif take a look and go 'ugh' and move on to the neighbours door, with it's lesser lock that can be kicked open in about 10 seconds.
We've spent about $30k now in the past 2 years increasing physical security (i.e. fuck off razorwire topped fences around the whole campus) and it's made a big difference. Until someone tried this: