I agree that it's unlikely all the work of one person, but I don't base that opinion on geography so much as I base it on what I consider to be some fairly glaring differences between the bodies themselves.
1). In the Manorville cases we see an obvious attempt to conceal the identities of the victims. In the case of Jessica Taylor, we see an attempt to render a tattoo unidentifiable. Pimps often tattoo their names on the girls that work for them. Jessica's tattoo said, "Remy's Angel". Perhaps Remy was Jessica's beloved grandfather, but I somehow doubt that. Anyway, my guess is that the tattoo was obliterated in order to hide any connection to Remy. Of course, that's just a guess, but my point is that, in the case of the Manorville bodies, the killer went to great pains to hide their identities. That tells me he knew the victims and felt he could be connected to them if the bodies were found. In the Oak Beach bodies we see casual, unconcerned dumping. The killer was done with them, no way LE could connect him to these women, loss them out like trash.
2). MB, MBB, MW and ALC were all found nude, were all strangled, were all placed in burlap prior to being dumped. Now, I realize SK's do sometimes change things up, but I don't think this SK does. He does what he does for a reason...it's not happenstance, imo. The burlap is so that the bodies blend into the scenary to passersby who wouldn't be looking for them. But HE can pick them out. I think that is VERY important to our guy. It's his power...his trophy case, imo. He gets off on knowing what others don't know or suspect. I believe they were nude because they were killed while nude, and I believe the were strangled because it's a slow enough death to let him savor his moment of power over them. I absolutely can not see him dismembering a victim. He has no need to. But apart from that, I don't think he has the stomach to dismember. I think once his victims are dead, they serve no purpose to him, so they are tossed out like trash. He would get no rush from dismembering, he wouldn't risk the time and mess, and he wouldn't have wasted that much time on these women once they had expired. JMO
3). I don't see our SK killing a toddler. I think it would have had to have been one hell of a bizarre situation to prompt him to kill a child. There would certainly be no power trip or sexual rush for him in doing that, and the notion that he killed a child simply because one of his victims brought it along on a date is just ludicrious to me. My idea of this SK is that he is nothing if not patient. He would have simply waited for another time to kill his victim, imo. Likewise, I think it unlikely he would kill a man, although, I can see that being possible under certain circumstances...such as he's an "adventure club diner", if you catch my meaning. But I think that too is probably unlikely.
So yes, I can see a whole host of things that make it seem unlikely all these murders are related. But I don't KNOW that they aren't related, so I have to at least consider the possibility that they might be.
MOO, and all that jazz.