There's SO many dog friendly things to do around here (DC/Annapolis/Baltimore) area. Actually, the Congressional Cemetery has a huge dog park where dogs are allowed to be off leash. I've yet to go there but have been wanting to visit - it looks so neat!
Congressional Cemetery & Dog Park Welcome | Congressionial Cemetery Dog Site
A doggy daycare and indoor dog park:
http://littlerascalsdogpark.com
Here's a list of dog parks in Maryland (I frequent 3 of them):
Maryland | Dog Goes
I don't really have any groomer or vet recommendations in that area, as I am in Annapolis more so, but I'd love to try and help if you need me
I went into DC a few weeks ago and saw dogs all over the place, another place I've been really wanting to take Jackson into the city, as I never have yet. All the memorials, etc, dogs are always walking around on leash. They just can't go into the water and stuff in the WWII memorial.