DIY is definitely an option here.
There are no building codes I'm aware of that are applicable to mic lines as they're carrying such minimal voltages that you could, for all intents and purposes, stick them up your ass without fear for your safety... they carry less voltage than the wiring necessary for your alarm system, so what's more of a priortiy are the RF rejectin properties of the wire, it's overall phase response, and lack of capacitance over long distances.
If you have an old Fender guitar amplifier and a Stratocaster [basically anything with single coil pickups] that doesn't get radioi stations... then I'd probably recommend something like a Mogami kind of cable... if you get a radio station [TV station, etc.] in the guitar amp combination... then I'd recommend that you go with some kind of "Star Quad" design [I generally recommend the Canare version... but from what I understand the Mogami version will do about as well].
To "DIY" this kind of operation you will need to have soldering chops. I would also highly recommend that you put in more lines than you would ever think you'll need as you can never really anticipate how your facility might grow, nor can you fully anticipate what you requirements may be 5-10-15 years from now [and if you're talking about running these lines through walls, you're talking about them being there for quite a while].
The other recommendation I would make is that when you do this... order about 15-20 feet more wire than you think you'll need and leave it either in the wall or in the floor so in case you move things around later in the life of the room... you'll have wire for whatever may happen. I know several places where if they had just left an extra 15 feet of wire kicking around when they changed from a desk with a right hand onboard patchbay to a desk with a left hand outboard patchbay they would have been able to accomodate the new desk with the old wires... instead of having to rewire the whole facility from top to bottom.
Best of luck with it.
