Dave
I can't help you on D.C., but if you must get a Turbine Conversion, shop around a bit. There are Schools not that far away. One if I remember sells block time in the 500, so it wont really matter unless you specifically need 206.
Post this on
www.justhelicopters.com also.
Personally I suggest shopping around and actually when your finished with your project in D.C. Find a place on the East Coast that you can get a deal, maybe even Heli Adventures in FL, go there do your thing and then fly back and out of D.C. If your ticket cannot be changed.
Take a look at
www.landings.com maybe they have some schools listed.
Good Luck and your Lucky you missed Vegas this summer, record Heat. As for me Im down in Africa enjoying the winter........