It is hard to say what the exact use of the Beech Janets is versus the 737 Janets. It is known the Beech Janets go to the less routine locations.
Palmdale is the most routine location for the Beechcraft. However, they make regular runs to Groom and the TTR. When N27RA crashed, it was ferrying
JT3 employees between Groom tot the TTR very early in the AM. I've tracked the Beech Janets to Northern California wine country a few times, and
photographed N661BA at the Nut Tree in Vacaville.
Janet airlines
From listening to the Groom Lake on the scanner and from the security procudruing discussed in "Red Eagles", being on one of these secret aircraft
isn't enough to get you on-base. When you land at Groom, they go to the badge office. In "Red Eagles", if your palm scan didn't work, you were
arrested until they could confirm your identity.
It is really easy to tell which Beech Janet is landing at Groom. Take the callsign of the month and add the last number in the registration. So N661BA
landing at Groom with callsign of the month being "mother" would be Mother 1, N20RA would be Mother 0, etc. The WWW flights have less of a pattern
to them, other than 2xx for arrival and 3xx for return flights.
A bit more on shooting the Janets. You need toi listen to the approach and tower for a heads up. It is pretty easy to spot a 737 janet early enough
to get a shot with the tail number. No so with the Beech, but you shoot any Beechcraft you see.