The memoirs of "Ginseck" are interesting, and remind me of the time as well. However, I don't think this adds much to the case. (By the way, "Ginseck" and her family are mentioned by her real name in early reporting on the story in the Washington Post). With all due respect, however, I think there is a lot of nostalgia in her account - I was intimately familiar with the area in 1975 also, and there were plenty of problems, and plenty of sinister activity (note that people keep bringing up this one-time resident of Jennings who was a child molester). Plyers Mill/McComas area could be a rough area at times - there were gangs (mild by today's standards, but still pretty scary). Frankly, I don't think the intimate knowledge of life there provides any special insight into what happened.
For the report on the evil-looking guy sitting on the slope just outside the Plaza that day, (and Firstman's opinion that it provides evidence of shoddy police work), I would just say that if you sent a police unit to investigate every dangerous looking person at Wheaton Plaza (in 1975 or today), Montgomery County would need a second police force. A few weeks after the Lyon girls disappeared, someone opened fire with an automatic weapon at the east side (Viers Mill Road) of the Plaza. I can't recall ever going to Wheaton Plaza as a child without seeing at least one frightening person on the premises. Older girls were hit on mercilessly. There were occasional flashers. You could even see guys from central casting in raincoats and fedoras, looking like they might have watches for sale in the lining. It was generally pretty safe in day time, in numbers, and serious incidents were relatively rare, considering how many people passed through there. But the Plaza is where everyone went, the innocent and everyone else.
The police effort was extraordinary, even if they did not hypnotize every Wheaton resident in the aftermath. They were hampered by few reliable, and conflicting, reports of witnesses, and the high winds and rain that made the dog search useless. They were also not prepared for a case of this kind, but nevertheless expended more resources on it than any case in county history. All the leads and supposed leads that the public knows about were explored exhaustively. It is easy to second-guess now, especially with the forensic tools available today, but this was a needle in a haystack from the first hour, and they can only do so much. It was an extremely skillful, or extremely lucky, abduction.