Alexandria is great location! Very pet freindly, but its not quite San Francisco... There are advantages and disadvantages like anywhere.
You will end up paying a lot more for a room during the summer tourist season around here. Obviously with kids and summer vacation it's prime time. That will drive the room rate. It will likely be HOT as well, so the yorkies will not want to walk very far (my little guys have lots of energy when its cool out, but in the heat and humidity of DC this time of year, we go on very short walks).
It may make more sense to stay a bit out of town and schedule for bus rides into Old Town and DC for dog freindly tours. Getting a large block or rooms for a bunch of yappers in a prime tourist location is going to be tough.
Just my 2 cents without reading all the other posts. In any case, I will be there unless I'm on travel from work, but no room for me! You may find better rates in Crystal City which is between the airport and Old Town, Alex and a short metro to DC, there are LOTS of hotels there. Too bad there are no pets allowed on Metro, LAME.
Good luck and if you need another volunteer, I'd like to help but maybe closer to the date - given that I have a demanding job and 2 little yapers to take care of
