Just curious. How do you get a Cat5 cable to your doorbell? My electrical wires are not in a conduit so do you have to drop down a cable from the attic? Not even sure I have access to that that based on how my roof design.
Perseverance! I've spent days in my attic running stuff. First for ethernet. Then a door bell. Then lighting. Then speaker wires. The HD video wires for TV. Then the soft-water line for my pool's auto-filler. Then more lighting. Then more ethernet. The second time for the POE cams. Luckily I have blown in insulation (NOT fiberglass), and my ridge is high enough that I can walk down the center. Otherwise I wouldn't have done some or most of that. Or whined about it more...
Getting to the inside of the walls varies. On the ends, where the roof doesn't slope down, it's easy. The other sides mean crawling on your belly through the insulation. One of my small claims cases was over missing insulation, which in this case worked in my favor, since half the insulation in my attic wasn't in my way!
So you get to the top plate (two horizontal 2x4s sandwiched together) of whatever wall you need to get into, and drill a 1/2" or 3/4" hole through both 2x4s. If your walls are not insulated, you tie a 20p nail to 10' of strong line and tie the other end to the wire you're running. You drop the nail down the hole with all the line and the first foot or two of wire. You leave 8' or so of wire stretched out in the attic, no loops or kinks, and then crawl back out. From the inside of the house you saw open a 6" x 6" square of sheetrock and stick your hand in there and feel around for the line. Then pull it and the wire down. If you have wall insulation (I do, and it's fiberglass!), it's so much more fun. You use a fish tape instead of the line. You can try taping the wire to the tape, and shoving that down the hole, or just the tape (which ultimately is easier). Back inside you hunt around for the tape, tie a string to that, go back into the attic and pull the tape out of the drilled hole and then tie the string to your wire, then back inside and pull that down. You tape up the string to the wire to make a nice smooth shape, so it won't catch your insulation on the way down and pull it out of place.
Once you get the wire in hand inside, then you drill through the outer wall (you cut your sheetrock square right behind where you want your cam), then connect it up. Patch the sheetrock (I have a trick for that, too, that makes it relatively painless), and then paint the wall corner to corner (or just the patch if your paint matches well).
If you're trying to come down through a bay next to a door (like where a doorbell might be), that can be tricky, because they typically frame one or two horizontal 2x4s next to doors for strength, which serve as blocks to your wire pathways. So you have to cut more sheetrock holes, one at every block, and drill through those and work the wire down through the blocks, one by one. It a few more sheetrock patches, oh well. You cut the holes carefully and use the cut out sheetrock as the patch, so you don't even have to buy any sheetrock. You're going to patch and blend and paint anyway, so a few more holes is no big deal.
Yah, do that 15-30 times, by yourself, then call me! Of course, a helper makes a huge difference, but it's possible to do by yourself. I wore a path through my attic insulation! I tried to rake it (literally) back into place as best I could, with some success. I ended up winning that small claims case after I was all done running everything, and had a contractor blow in a new layer, nice and neat.
Interior walls are easier because they don't have any insulation in them, and are generally easier to work over in the attic. You can usually figure out where you are in the attic, by orienting yourself with can lighting, furnace ducts, plumbing vents, etc. Then you move the insulation around and you'll see the sheetrock and the top plates of all the walls. If that proves to be to difficult, before you go up, you drill a very small hole in the ceiling and shove a wire or coat hanger through it, far enough up to penetrate the insulation, so when back in the attic you have a tell tale to look for. Then later fill the little hole with some spackle and some times you don't even have to paint those.
One of those headlamp thingies is mandatory. I carry a tool bag with everything I need, plus an extra flashlight so I don't get stranded if my headlamp goes out. I carry my phone so I can call for help if I need it. Or get stuck!
That's most of the tricks. I've done it so much I have it down. I'd like to say it's not as bad as it sounds, but it is... It's a lot of trouble, but hardwiring everything makes it all work better and faster.