It looks to me--with no real evidence to back it up--that the B&B was the Wydnor Hall Bed & Breakfast (3612 Old Philadelphia Pike, Bethlehem, PA) right? If so, I'm sure you found this fascinating item: https://www.estatesale.com/sales/view/252854.html. There are a number of items in that auction that are definitely Miskolczy-related, including Laszlo's framed 1922 diploma from Technical University in Budapest (you can view it without the frame here). Images of these items are currently downloadable, but since the auction ended months ago I don't know how long they will remain online.
From the listing info, I'm gathering that the B&B owners bought the property in 1986 and converted into a bed & breakfast at that time. It was "an 18th-century property that was once part of a 90 acre estate," and included "original paintings from 19th c. Hungary." Any bets that B&B was not directly associated with Miskolczy descendants, but that the estate was the Miskolczy family's and had been there for decades prior? Some of the artwork seems to be by Laszlo's brother, Ferenc. Perhaps some Northampton County, Pennsylvania property tax records could turn something up definitively.
Apropos of nothing, but I wonder if your Laszlo is related to Gabor B.L. Miskolczy, June 15, 1933 - July 23, 2012, Carlisle, Massachusetts. Note in the obit: "He leaves...first cousins...M.E. and Kristina Taylor of Bethlehem, PA and many other dear friends and relatives." Some of the artwork in the B&B auction is by Kristina Miskolczy...I assume the Mrs. M.E. Taylor.
If so, this is quite the family. Gabor's father was a well-known neuropsychiatrist and, divorced, his mother remarried to Albert Szent-Gyorgyi, the 1937 Nobel Laureate who discovered Vitamin C. Gabe himself was the first full-time employee of Thermo Electron Corporation, then a start-up in a garage in Massachusetts, today Thermo Fisher Scientific, a $24 billion company with 70,000 employees and, in our genetic genealogy testing world, the only direct competition to Illumina. Being the DNA nerd that I am, I just had to throw that in there.
Edited to add: Nope; I was wrong. The B&B was in the family. Looks like it was owned and operated by the aforementioned Mr. and Mrs. Taylor, formally acquired in March 1986. It stayed in the family, in one form or another, until just last July.