Altritter- you haven't ever worked with Bobs?
Yes, I have. In fact, I bought my bike there a couple years ago. Both Bob's (Jessup/Fort Meade, MD) and Morton's (just south of Fredericksburg, VA, on US 1) service airheads & have good reputations. So does Battley Cycle (Gaithersburg, MD), though I don't know how much airhead work they do now. I'm pretty much equidistant (50 miles) from Bob's and Morton's. Problem with Bob's is that I haven't found a comfortable route to and from. It's either the insanity of I-495 around DC, or the Balt-Wash Parkway (which would be a good way, but for having to go through DC's nightmare of cycling hazards to reach it—steel plates, wheel traps, potholes, and literally tons of loose gravel on the streets).
I tend to favor an indie shop in Alexandria, VA, EuBMW (it sells a lot of mail-order parts, too). The current owner, who has a master's degree in engineering, took over the shop when his father died. (It was formerly Lap's Quality Cycle, a favorite of Washington-area BMW riders for decades). He currently has a number of vintage airheads on display or in for repair. Also, he has a to-die-for BMW/Isetta 650 in the shop for a rebuild. Cosmetically, it's gorgeous.
So, I think we're fortunate in this area in having a relatively large number of repair facilities available. I monitor the BMWMOA Airhead Forum, and from what I read, airhead riders in several other parts of the country don't have it nearly as good.