This link was my route of flight from GAI to JGG and the same back. We did it at 1500' in the am becausae of low clouds and at 2400 on the way back to catch a tailwind component.
http://skyvector.com/?ll=38.3730499...lan=A.K6.KGAI:F.K6.VPONX:F.K6.VPOOP:A.K6.KJGG
Don't be intimidated by the SFRA - although as mentioned before, a GPS is highly suggested. These were my steps on the route back:
1. Called 1800WXBRIEF and filed my DC SFRA flight plan from Whino gate to KGAI at 2200z, 25 mins en route. That gives you a window from 2130 to 2400z to get there. I normally do this en route to the airport.
2. When I was just passing St. Marys Airport, I called up potomac approach on 125.12 (on the TAC under SFRA south, or I have a cheat card i carry with me with the various sectors). "Potomac Approach, Skyhawk XXXXX, off of St. Marys at 2000, inbound Gaithersburg"
3. They give you a squawk code and tell you to remain clear of the SFRA.
4. They say "transponder observed, proceed on course, remain clear of bravo, washington altimeter 2x.xx". That is your clearance into the SFRA.
5. Stay on the frequency and don't touch the squawk code. They may hand you over to a different frequency along the way.
6. When you are within a few miles of your field (if in the SFRA) tell them you have the field in sight. They will tell you that a change to advisory frequency is approved, keep the squawk code until you are on the ground.
Andrew