I believe I read that the body was buried on the edge of the property.
I am of course describing things as they are now or in the last few years, according to a recent satellite photo, and not according to how things would have been 30 - 45 years ago.
If you were to park up on the ramp around the expressway on the south side, under the highway bridge to hide your vehicle, you would see a wooded area after about 100 yards. However that wooded area is not so dense and after 125 yards or so you're in a clearing. Maybe this wasn't such a good hiding place after all... but the clearing ends after 100 yards and there are more trees. So you keep going to make for a better hiding place.
Only problem is, you are now near or even on the property. You decide that you can't find a better place as the only thing riskier than going into woods with a dead body or kidnapped girl is coming out of the woods with one - anyone could be investigating your stopped car or truck by now and you would lose control of the situation. So the deed is done there out of necessity.
It doesn't require access to a construction site or any special familiarity with the land. It gets riskier if the houses are occupied of course but even then may not be as bad for the killer as emerging from the woods with the victim.
If the killer did this and was intimately familiar with the area, they'd have known that, from the satellite view at least, the woods go much further back to the north side which would be at least as accessible.