minecraft-java-edition
Depending on which way I'm facing when I place a door, it will either be on one side of a cube border or another. Are there any game mechanics that make use of the door's alignment which I should be aware of, or is it purely cosmetic?
Door placed from this side
Door placed from opposite side
Cover the walls with signs. Spiders can't climb a wall if it's covered in signs. I just tested it.
If you're willing to put the button on the bottom block, this isn't too hard. Try something like this:
Here's another shot from the top:
And here's one from the back:
When either the button is pressed or someone stands on the pressure plate, the door will open.
If you want the button to be at eye level, you can make a minor modification, as suggested in the comments:
This will allow you to move the button up one block, at the cost of two repeaters. Keep in mind that this will add a (very) small delay to the circuit, but considering it's a button, this might even be an advantage.
Best Answer
I believe doors allow attacks in one direction. So if you mount the door from the outside, you can attack through it, but you cannot be attacked (or be shot by skeletons) from outside.
I can't find an official source on this, but this thread discusses it (see the last post), and this blog entry (see number 5) seems to confirm it.