I do wish I could help you on barn suggestions as I think you’re being a bit shortchanged on this thread. But alas, I have been out of the in-a-program circles for a long time and never shopped in that particular price range.
If you are indeed going to pursue Gaithersburg I could at least suggest some areas to consider searching in. I lived somewhat near this intersection for about three years and rode in varied locations. You would probably want to limit yourself to a 20mi radius of your home location and preferably less than that. I rode in Boyds (20m early weekends, 35m+ weekdays), Poolesville (45m, 1.15h), Mt. Airy (45m, 1.15h), Brookeville/Olney (25m, 45m) and Damascus (25m, 45m).
And yes, the driving is incomprehensibly bad. It’s not a “sore subject” - it is a fact. From the location noted I commuted with HOV privileges to Bethesda (18mi). Even with three different accesses to the highway it usually took 55m. Easily half of that was spent on the 3-4mi between highway and house. In fact I moved back home to Frederick County because the traffic on local roads was so heavy morning, noon and night, weekdays and weekends that I nearly lost my mind. I now commute, sans HOV, from Urbana (south Frederick) to Bethesda - 31mi (2mi off highway at either end) at 5:45AM takes me an avg 1:05. Rush hour starts before 5 am, slows around 9:30 am and ramps again from 2:30 to 7:30 pm.
To be honest the traffic becomes a bit second nature so I’d think more about the atmosphere of the area you are choosing to live in when making a decision. Some pockets of Gaithersburg are quiet, mature, even slightly rural but much of it is strip-mall living, busy neighborhoods with overcrowded neighboring apts/houses and much, much cultural diversity up close and personal. Areas like Rockville, Bethesda, Arlington are the more stratified condo, nightlife, city living locations. Suburbs west of 270 lean more spacious and “slower”-paced.
Most farms in the area that would meet your criteria have websites or Facebook pages. I would suggest doing some intensive searching and returning to the forum with perhaps a new thread asking for input on those barns that you’ve identified as potential fits.