The tall gate is worthless because it opens up. With a regular door you can keep it from opening by putting objects on both sides of it. With the gate that doesn't work and the baddies (during a blood moon) just open it up and come on through. And no, there is no way to lock it. I tried! :P

Pity.

I put a trap door just before with some lava and that worked out well for the ground enemies. I need to kill that skeleton guard so I can find the mechanic and start to build some intricate traps that will deal with flying enemies as well. :)

Remember to buy a Wire Cutter when you free her. That way you can use it to harvest the wires in the Dungeon while you're exploring it (saving a bunch of money).

I know but that isn't really a problem for me currently as I have lots of money but I can't kill Skeletron yet.

I never did figure out the wiring part of this game.

You haven't been reforging much then. Granted, there's not much reason to do so with the pre-hardmode weapons (unless the best base weapon you have has a negative mod), but getting an additional 20 Armor or +20% Damage from accessories can help a lot at that stage.
This is a decent option as well. Enemies are incabable of battering down a door if it is 2 tiles above the outside ground. Their AI will instead jump up and down right outside and it won't be much of a hindrance for yourself

You are right, I haven't. I will try and see if that helps, thanks.

You know what this game needs? A draw bridge that slams open and slams shut, killing everything in its path! Imagine wiring that to a pressure plate. It would look like your house/castle was devouring the monsters >:D

Place a bit of furniture on the inside of your building entrance, it will block the door from being opened from the outside.
Iirc it will also prevent the mobs who are able to smash down doors from being able to do so.
The only inconvenience is that in order to open the door you need to be facing away from the blockage.

If, for aesthetic reasons you'd rather not have a random table or chair next to a door, use actuators and blocks with player only activated switches on either side to create an entrance which can't be opened by either npcs or enemies.

Since 1.3 npcs can actually defend themselves. On their own they might not fare to well during a blood moon or goblin invasion, but grouped together they tend to be able to deal with more than you'd think they should. Pirate's, martians and solar eclipse will still wreck them though, so it's best to flee your base and deal with those elsewhere, or hide underground if it's getting too much.

build "wall doors" ...place activators over the blocks so u can switch them in the background and vice verca....built some giant steel gates for my castle this way...

only problem is that u can use them only with switches or pressure plates

And of course if the power goes out you're screwed.

Don't laugh; I can imagine this will be coming with the next update. :P

ok then.... best solution: get a rod of discord and u will never need a door again