Level Plan:
This was my original map from Level Design 1.
Originally, my plan was to have the player explore the desert and try to find the saloon, where he or she cold then explore the insides and have a drink. The player could enter the saloon two ways; the front door, or the back door via sewer. However, I’m not sure if my initial goal was too ambitious, so I have decided to alter what happens to the player once they reach the saloon.
Once the player walks inside of the saloon, they will be blinded by the light coming from inside. The music will get louder, and they will be transported back to the starting point. If the player chooses the alternate route, they will be blinded by the light and be brought back to the spawn point as soon as they walk up the stairs from the basement (where the sewer leads them).
Here is the updated version of the map. Note the sewer’s outline here. 
The overall mood for the setting will be dark. The level will only be lit by the moon and light coming from the street lamp and saloon.
Modular elements:
These concepts are rough sketches of what I plan to create. The assorted bottles will be found in the basement of the saloon, as stock inside of shelves.
Color Swatches:
Because I’m going for a gloomy mood, the colors needed are dark. The midnight blue sky will go well against the sand and buildings.
Reference:
Combining the art deco style with the western style may be the biggest obstacle. The saloon has to have the right mixture of both in order for the mood to be set correctly.
Cool aesthetic! I really dig the juxtaposition between the art deco and the beat-up western look. Really saturated colors in the saloon area would be a good way to signal a change from the bland desert and wall environment of the outside. Alongside the music, it should be a really cool change. Bright reds, greens and blues to further emphasize the “Fountain of Youth/Life” sort of feeling the saloon should have would be good.
So are you just leading the player by audio cues? You might want to lead the player a little more. Maybe a long road by the ocean and then up to the saloon’s front door, so they naturally see the route to the front door first, and then have a second route to explore afterwards.
Your concept for the western saloon in the metropolis area is really novel. The use of audio (with the music)is a way to guide the player around.
I’m still getting a Fallout/Book of Eli feel with the work you’ve done thus far. I think you should check the former out for desert reference. I think I’m reminded of the latter because of its similarities in color choices.