You'll need at least a Private Pilot Certificate with privileges for the lighter-than-air category.
If you haven't seen this, check out
http://www.personalblimp.com/
I'm acquainted with the inventor and am hoping the enterprise succeeds.
You didn't say where within McLean, so it's difficult to answer your questions exactly, but you are probably within the DC Flight Restriction Zone, which is the smaller region within the DC special flight rules area. In the FRZ, unless you're based at DCA, Potomac Airfield, Hyde Field, or College Park, you're probably out of luck as far as takeoffs and landings. If you're based at those, you have to go through a special vetting process and learn the procedures to prove to flight service, ATC and the interceptors that you're who you say you are.
Within other airports somewhat farther out, but still within about 30 miles, you have to follow some special transponder and flight plan filing procedures.
You might be able to get a waiver for a special event within the SFRA, but I'm betting for a flight within the FRZ all you'll hear is "no."
If you're not a member of the Aircraft Owners and Pilots Association (
http://www.aopa.org ), it is probably worth your while to join now. They have some discounts on training materials, discounted legal services, and some competitive insurance deals.
As a homebuilder, I'd also suggest you check out the Experimental Aircraft Association. While I think that most of the members are fixed-wing people, there are definitely all sorts of homebuilders and pilots in that group.
The AOPA site has a LOT of information on flight restrictions, NOTAMs and government advocacy.
Also, if you find a good lighter-than-air instructor, please let me know. I have always wanted that rating.