I’m assuming this is meant to be fairly realistic, so we can look at reality for some ideas…
Have you ever seen a street that looks like that? I haven’t. Even the most boring, cookie cutter ‘McMansion’ developments have more variation - driveways, garages, gardens, pathways, backlots, shrubs, flowerbeds, etc. Even if it’s an army barracks, there are likely to be more details - flagpoles, parade areas, admin buildings, etc.
This obviously requires more assets, and more work, which could be a problem if you under very tight deadlines.
In terms of only building a small section of a much larger world, it would be good to have some form of internal logic. Not necessarily real world logic, but something that ties into your story, world or gameplay mechanic.
Surreal: a small enclave on the top of a high rocky pinnacle, surrounded by crawling clouds. Only the top of the rocky tower is green and lush, like a piece of suburbia ripped from the ground. The background is so far away is can be a skydome.
Gameplay: there is some force field, timer or allowable zone (such as a person under house arrest with an ankle tracker) that only allows movement in a small area. We can see further down the street, but can’t ever get there (allowing you to build to a much lower LoD)
Real world: we are in a cul-de-sac in a suburban neighbourhood, and the only exit is blocked- by a tree, military roadblock, quarantine zone - whatever works for the narrative. Because the road turns a corner, we can’t see that far - and the houses all have garden fences that block view and progress.
Sci-fi: a test area in a large sci-fi bunker. The walls are concrete and metal, and drip with rust - but the lights on the ceiling give a reasonable approximation to sunlight.
…there are thousands of ways to do what you are asking, from simply blacking out the inaccessible areas, a wall of dense fog, a glowing forcefield, etc. None of them will make your map look better, though - that needs more work, and a lot more assets and texture variation.
Hope that gives you some ideas.