If i may ask...
how do you get the patience and time for building such things? i am an animation student - if you are familiar with how animation is made, you know it sometimes takes 6 hours of hard work to produce 2 seconds of proper animation, so it is pretty tedious - and i can't seem to find the wilpower to carry on super massive builds.
a month ago, i built (started to) something the same size as yous ISF Curator. it was a wrecked, burning, semi-operational steampunk zeppelin. that thing was MASSIVE. no kidding. it took me hours to build just the shape. you could literally walk inside and interact with stuff like the weel and such... and then i lost temper with it, leaving an entire section of 400x1200 blocks unfinished, where would be the main machine room with ruined components and leaking boilers to the floor below. in the meantime, i even deleted it.
just... HOW can you stay focused? i even tried Gameiki for the sake of allways having light, no enemies to distract me, and infinite tile reach and speed, and it still felt tedious.
Well, first I make sure that I have plenty of time to spare for the build (which is why I haven't been able to build lately) so I can build uninterrupted. Once I've started building, I'll keep going until I've run out of creative ideas, or until I start feeling like it's going nowhere. When I've hit that point, I'll get up, take a couple hour break, then get back in game, and go over everything I've built thus far. For me, seeing the progress I've made towards an idea usually motivates me to continue improving on it, and usually when I go over everything after a break, I'll usually come up with a few more concepts or ideas for the build that hadn't come to me before.
I can't really answer how I stay focused, as it just happens. It's how I work. Progress spurs me on, but I couldn't tell you why I'm patient with it.
If you find building in game too tedious, you can always try TEdit. It's a third party program that allows you to build in Terraria in a sort of photoshop setting. Many builders on these forums use it beautifully. I'll use it for certain things, myself, and I find it an invaluable tool. Since I haven't had the time to really sit and mess around with Terraria for a while, I haven't bothered to find out if TEdit has been updated for 1.3, but it may be worth a look.
Sorry for the cryptic reply. I'm not certain how to answer the question >.< but hopefully you'll find the inspiration and motivation to continue your builds! ^.^