I don't know if the DPCA is recommending a Veterinary facility for this year's Nationals, but there is a 24/7 emergency clinic (the only one in that area) literally 2 minutes (probably about a mile) up the road from the hotel and ring.
I work there and it is a very, very, good facility! I have worked at two other veterinary clinics in the area, and this is by far the best place I have been.
The Veterinarians there are fabulous; they really care about your animals.
Tufts is far and expensive, and Acton as well (extremely expensive!!)