The designers set up paths to lead you through the stores from the landing point on each sim. They even have the sim crossings marked well so you can slow down and not take too big a hit.
Here are a couple of the kind of normal interiors I saw with shoes out, posters on the wall, etc. Sometimes, as in the first two pictures, you can see the walls of the supplied building.
Another kind of typical interior but this company covered the walls, not the ceiling. Interesting feeling - like movie posters in the black frames with the silk ropes. And the robin's egg blue walls and pink lights stand out in the mix of stores with dark walls and light floors.
Other stores very much change the interior look. They cover every inch of the interior with the look and feel of their main store. Bax Coen did this.
A couple of stores built boxes smaller than the provided building and that is all the customer saw. This gave them ultimate control since they could change the slant of the walls or roofs, the lighting and textures. Here is a store that used this technique. The shopper sees a stone lined space, not too deep with niches and other stone trim. If you swing the camera back behind the wall, you can see that this is a box they've placed inside the provided barn building.
Here is another store that went the box route. This is me standing at what looks like the back of the store going into a fitting room kind of door. I'm looking into the store.
I'm standing where you see that red shape sticking in the air. The store itself is very small and intimate as you can see...lots of original building not used. They shaped the box - wide at the front, smaller at the back.