Just caught up on thread. Some scattershot observations, apologies for not replying directly to previous comments:
Carnival worker - I'm a lifelong New Englander, currently living 30 mins from Allenstown and Manchester. "Carnies" would generally work at carnivals or fairs. As someone said, this would be a summer-time gig in the NE area, usually set up to coincide with "Old Home Day" weekends in many small towns or larger agricultural/entertainment fairs in some cases (e.g., Deerfield, adjacent to Allenstown, has a massive one each year). Mechanics, electricians, handymen would definitely be needed to maintain and repair a lot of the rides and vehicles associated with these events.
Danish ancestry and "Eastern accent" - The claim of Danish ancestry is puzzling to me. I agree that is probable in general that there is some truth in lots of what RE told people, and the Danish ancestry thing may be one of those instances. However, it is NOT a prevalent or active group in this region, nor do I suspect it would have been 50 years ago, when RE was coming up. As some have said, French-Canadian is the stand-out ancestry in northern New England (ME-NH-VT). Many middle-aged folks in the south central NH remember growing up in homes were French was regularly spoken, lots of French surnames, road names, etc. NH has fewer early 20th century "ethnics" than southern NE, which has a lot (Irish in eastern MA, RI and CT; Italians in NY area, southeastern CT and coastal cities, Poles in central CT, etc.). There are certainly pockets of other ethnicities in NH beyond French-Canadians (e.g., Greeks in Manchester), but New England does not retain a strong footprint of Scandanavian immigration such as is obvious in the upper Midwest.
I'm not saying RE is not Danish, but his being Danish would not mark him more reliably as being a Northeasterner. In fact, to me, it would be a convenient way to obfuscate one's (American) origins. Since he was somewhat tall, light-haired, and blue-eyed, saying he was Danish would be a way to garner instant credibility without giving anything away about where he was actually from. It'd be like if a really tall blonde guy from Pawtucket, RI told me he was Swedish. I'd believe him, find it interesting, and would be none the wiser as to whether he was from Rochester, MN or anywhere else.
The accent is more telling, I believe. I would propose three likely "accents" an outsider or a fellow east-coast expat (such as the Nor Cal detective) would pick up on, two being actual accent types and the other being more of a distinct cadence, common to most northeastern speakers: 1) Northeastern city accent; 2) Backwoods New England accent; 3) fast talking. I suspect the detective picked up on one of the above. The city accent varies by city (Boston/Providence is more "pawk the caw"..NYC, though somewhat different, also drops the "r" at the end of words and would be striking to anyone outside the area...that said, the accent is so famous from movies and what not, that I'd be surprised others wouldn't have picked up on this tell, even non-east-coast natives among whom RE lived for so many years). Backwoods accent (Maine, much of western and northern New England) sounds similar, but may be a little more subtle. Finally, non-northerners will often highlight the speed with which Yankees talk as being distinct (and probably abrasive!). This is less an accent thing - Vermont, western MA and central CT is largely devoid of a recognizable accent - than a pacing cadence, with some pronunciation quirks (e.g., northeasterners may call a town named "Wilton" Wilt-En, while outsiders may call it Wil-Ton).
Concord Monitor Article on Ms. Randall / Oakhill: The article says "it is not clear how Randall got to the RE name in 2014." I respect the work of Oakhill and assume they know what they are doing as far as informing the police and keeping things close to the vest in certain cases, but it would've been nice for the article itself to, I dunno, ask her about how she got to RE in 2014!?? I had not ever heard this detail until another poster mentioned it, nor do I recall Oakhill ever mentioning it before the press conference in January.
Another interesting tidbit from the article is that there were other tracks in Allenstown when they were hiking there. Anyone know about how the site is treated today? It's private property, yes? Have there been many instances of pilgrims and/or run-ins with police / town / residents over trespassing there?
Oakhill comments - I find them tantalizing, but tend to discount them ultimately. I think this crime (A4) was pulled off in secrecy; if there were "rumors" about the strange handyman from Manchester, they would have been sussed out earlier. Instead, I think that while a lot of people may have been in Allenstown/Bear Brook at that time, and there may have been some hearsay, I don't think anyone really knew what happened. Not to say there aren't people out there who knew RE (or whatever he went by) in NH who can help advance the case.
Aliases - Why does he need (non-fictitious) aliases? What does he get out of them? SSN, Birthdates to obtain official ID to obtain employment? Real, fresh names to give police if pinched for something small? I don't get why he would keep the birthday but change the birth year by a decade, for instance...Wouldn't this un-do the whole point?
Veteran - I don't know if it's already been mentioned (nor if I'm hallucinating this) but I believe in the most recent press conference, investigators cited as possible evidence for RE having been in the military was the way he tied knots and performed other manual tasks and tricks that was reminiscent of military training. I wonder what things they've been able to track down to propound this notion. Perhaps this is based on his personal belongings when he was arrested for the Eunsoon Jun (sp?) murder? Maybe the ways his victims were bound?
I'm also curious as to the nature of his time in the military, if indeed he was. To have been in active duty in Vietnam, he would have likely had to been born in the latter half of the birthdate range I would think (1945 - 52). Is there any forensic or psychological evidence in his case or MO that would be consistent with active duty trauma of an extremely bad variety? As to his identity, could it be a Dick Whitman / Don Draper type of situation, where he was presumed dead by the family but returns back stateside to start a new life with a new name?