Take a large spacecraft. I'm thinking about 1,000,000 metric tons and 3,000,000 cubic metres, but I don't think a factor of 10 either way would change things.
The ship is heavily designed and capable of atmospheric flight. There are technobabble FTL and STL drives. The ship can maintain several G for several days. The drives do not operate during this scenario, I mention the acceleration and delta-V to give an idea how strongly the ship is constructed. Think of the Nostromo from the Aliens movie -- steel frames and hull plates, not lightweight composites. Under ordinary circumstances, the ship is capable of controlled reentry, atmospheric flight, and takeoff.
Now assume that this ship is left in low orbit, which decays over time because of atmospheric drag. (This will take some time, given the mass to surface ratio, but how long isn't the question.) At some point, the aerobraking accelerates and the ship crashes on the planet.
What kind of wreckage will result? Will most of the wreckage be in a confined area? Can there be something which intrepid adventurers can actually enter and explore?
Historically, there was the Columbia disaster. The Columbia disintegrated into relatively small debris. So did Skylab, yet the tank was recognizable. I would like a hard-science answer, but I realize that's too much to expect. So I made it reality-check instead.
Alexander asked in the comment if it was tough and relied on aerobraking, or if it relied on braking with engines. My assumption is that it is tough, yet usually uses engines to brake -- toughness so that it doesn't need an overhaul after each landing, engines for controlled flight.
Separatrix assumed that there would still be a crew. I was thinking of a derelict, no crew and the power for the computers and maneuvering thrusters is long gone.