I expect a vehicle with trailer would be very conspicuous parked in the driveway of an unoccupied house, even for a house slightly obscured from view from the road.
Why would there have to be a trailer? Would parking only a car 'so far up the driveway' be unusual? There is a stairway near to that point (flourescent marking at driveway) but if someone was transporting something large or unwieldly they might not use the stairway. The easiest point of passage is where the driveway meets the grass where there isn't a such a steep descent, and that's a short distance to the left of the stairway (pic perspective).
Something else to consider: would the driver have backed-in a vehicle / trailer from the roadway or would the driver have driven straight in and u-turned in the driveway?
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. . . . RESPECTFULLY OMITTED . . . .
"Why would there have to be a trailer? Would parking only a car 'so far up the driveway' be unusual? There is a stairway near to that point (flourescent marking at driveway) but if someone was transporting something large or unwieldly they might not use the stairway. The easiest point of passage is where the driveway meets the grass where there isn't a such a steep descent, and that's a short distance to the left of the stairway (pic perspective)."
The area to the left of the stairway drops off very steeply for approximately 10 feet but then gets smaller and smaller as it gets closer to the fluorescent pink spray paint. That said, I agree with where you're ultimately going with this.
"Something else to consider: would the driver have backed-in a vehicle / trailer from the roadway or would the driver have driven straight in and u-turned in the driveway?"
Due to the severe angle of the driveway, it is most probable that a vehicle (especially one towing a trailer) drove straight in and then u-turned in the driveway. The driveway is very wide and long down by the pond. There would be enough room to u-turn down there.