Like I said, I'm relatively certain that this kit wasn't intended for stand alone use. The real trick to making such a home livable is to combine this kit with standard building techniques.
In my picture above, I only used it to design the curtain wall of what would become a castle. If I had decided to continue with that particular lot, I would have built the keep using standard walls, and more than likely incorporated several different structures. Once this was at least partially built (if not completely finished), I would have continued to use the kit pieces for decorating by finishing off the flat roof of the main building with parapets, adding a few towers to it and possibly even increasing the height of the curtain wall and making a multi-tiered battlement.
What I choose to do instead was to actually create a sim, move in a few townies, and started building a livable castle. I picked the same lot, but changed the design of the curtain wall to include a gatehouse and several postern to allow access to the larger areas of the moat I created in the corners of the lot . And I figured out a couple of things:
The first thing I noticed is that it's much easier to build a castle on a large lot. The larger, the better. I used my favorite 60x60 lot in Sunset Valley, but Riverview and Barnacle Bay both have these sized lots. Twinbrook and Bridgeport are lacking in lots this sized, so you could run into some difficulty using it there. But it's entirely possible if you can think of a way to scale it down.
Another thing I've learned is that the texture on the kit can actually be copied and applied to a normal wall covering in order to give the keep itself the appearance of being of constructed of the same material as the curtain wall. Likewise, the texture can be changed to something else, for example: wood planks, in order to simulate a palisade (a wooden curtain wall).
Also if you turn moveObjects off after the wall is placed, you can fill in the moat so it goes right up to the wall. Afterward, you can use the soften terrain tool to give it a more natural look.
And finally, placing the kit pieces at an angle,
especially the doors, is somewhat tricky. There ends up being a great deal of overlap that causes some texture shifting as you move the camera past it. I learned that the best technique is to place the door first and fill in the area around it.
Another idea I will be experimenting with will be stocking the moat with crocodiles and piranha. That should help keep those pesky paparazzi away!
Actually, it's more to satisfy my personal taste in aesthetics. I've designed the entryway to allow for an electronic gate to handle those guys, although it's not in place just yet.
Once I've built something substantial, I'll post some pictures so you can see what I'm talking about.