Final SS2 project - Referencing

I've come to the point where I feel that the gathered knowledge from the past few months allows me to embark on a bigger, more complex piece of work.

The aim with my final project is to learn as much as possible about what it takes to create a working environmental level within a game engine. This piece of work will serve as the leading piece of my portfolio.

As a first step, I've looked at hundreds of reference images to get a slight idea about what kind of level I want to create. I need to be very ambitious about this project as it will stretch out until the middle of May, meaning I will have to concentrate entirely on it for two and a half months. It would be a very dangerous situation if I should end up disliking or unsure about the concept I've chosen, so this is probably the most important phase: what am I making?

Here are some of the concepts that made it into the final few I need to choose from:

What I like about most of these is the unique feel of the environments they portray. I look at them and instantly wish I could walk around that place for a bit, feel its atmosphere first hand.. or at least in a game.
Also, technically they are acceptable to create, even though some of them are bigger than the others.

After days of staring at all of them and examining what each would require artistically and technically as well, I've decided to go ahead and attempt a concept which was originally created for the game Fable 2.

What is especially good about this one is the fact that it definitely needs to be created in a modular way. This method is crucial to be mastered today. The level and its assets (especially the architecture) have to be created in a "re-usable" way. For instance: I need to examine all the buildings and decide what fundamental elements, what pieces they are all composed of. After this is done, I need to create a library of walls, support wood, roofs, stairs etc. and then re-use them all over the place. I don't have to create each building separately and uniquely, I need to create the lego pieces that put all of them together.
To eliminate the obvious repetition, I have to apply different textures and the job is done. This is going to be a modular level.