There is a really simple way to keep track of distance while traveling short lengths along Ocean Parkway: count the bumps as your vehicle crosses from one concrete slab to the next.
Anyone that has driven ocean parkway can tell you that the roadway is constructed of adjoining concrete slabs. Probably due to the age of the roadway, and because it rests upon shifting sand, the slabs don't form a smooth straight line. As you drive there is a consistent, bah-dunk, bah-dunk, bah-dunk, the bumps are exactly x feet apart. I don't know if x is 20 or 50, but it would be easy enough to count 10 bah-dunks then stop, especially for a person who suffers from hypervigilance.
My guess is the killer knows Ocean Parkway like the back of his hand because he lives there. Who is fidgeting with a GPS device when you have corpses in the vehicle? I would think he has his eyes on the road looking out for witnesses, but his mind is stuck on those **** dammed bumps he hates so much.
It looks to me like he got better over time at finding the right location.
Assume for a minute that there's only one killer.
The first victim was Jane Doe 2000. She was left "outside" of the dump site, if you want to define the dump site as between Cedar Beach and Gilgo Beach marinas.
Take a look:
http://www.newsday.com/long-island/suffolk/bodies-found-at-li-beaches-1.2541830?qr=1
Travelling west, the most obvious markers are going to be huge green parkway signs that say "Cedar Beach". You'd pass the marina entrance road, clear as day. Next up would be another huge green sign that says "Gilgo Beach". I haven't bothered to look at satellite images to see exactly where they are, but at night I can assure you that these signs would be the best indicator.
My guess...
The first body dump, Jane Doe 2000, was done hastily with little regard for exactly where he was depositing the remains. He knew exactly where Cedar Beach was, but was in the early stages of establishing his "graveyard".
On the second dump, Jessica Taylor in 2003, he passes the entrance to the Cedar Beach marina, but probably drops her off BEFORE the Gilgo Beach sign that I'm guessing he eventually comes to use as a marker.
He's getting more sophisticated.
Next up...
Asian crossdresser. The media said 5-10 years decomp, so I assume this murder occurred in 2004-2005.
At this point, he's getting more comfortable with the dump site. Noone has discovered the 2 sets of remains like they did in Manorville. He's getting to know the area better, since he's returned several times to try and "relive" the event, check the scene, etc. At this point, he becomes unconcerned with dismemberment. After all, "No body, no case".
With the crossdresser, he probably uses the Gilgo Beach sign as a reference point for the first time.
At this point, he's evolved. He has enough of an intimate knowledge of this particular 2-mile stretch of road to be able to pinpoint his dump site exactly using TruthSpider's "bumps" (which I agree would be an excellent way to pinpoint, but only in small numbers - he's not going to count >20 bumps is my guess), odometer, # of seconds past the Gilgo sign, whatever. But his method is REALLY precise. And thanks to TruthSpider for mentioning the bumps. I've driven that road a hundred times and those bumps are definitely like clockwork.
As for the other victims (the baby, Jane Doe 1996, the human bones found at Tobay), my belief is that that killer came from the east, and lives in Nassau County. If I'm wrong, then my assumption is that traffic may have caused him to go to Plan B - random dump.
Because of the evolution I described, my sense is that the serial killer knew how to get to Cedar Beach and knew it was a great dump site.... BUT, he wasn't a year-round Oak Beach resident, otherwise he could have pinpointed the final "graveyard" from the beginning.
I also sense that over time, he began trying to move the graveyard further from Cedar, closer to Gilgo in order to draw attention away from Cedar Beach, which he had a connection to. Nevertheless, he likely thought that noone would ever find the bodies, or if they did it would be 50 years from now. The burlap was just an added countermeasure. It would camouflage the body and prevent aerial scavengers like crows from creating a scene. As a deer hunter, I've seen crows converge in droves on a fresh gut pile in less than 30 minutes.
