Hi Fred,
I'll go ahead and post the info here. If you've been going to the NIH for three years, you might already know all this. But here goes...
My mom was lucky enough to stay at the family lodge on the NIH campus some visits, but at other times she stayed at the Comfort Inn at Shady Grove in Gaithersburg. It's a 20 to 30 minute drive or about 15 minutes by metro (2 or 3 stops), but you have to take a shuttle from the station to the hotel. Sometimes patients have to be at the hospital very early in the morning for testing, so be sure to plan ahead and don't forget to ask for the NIH rate ($79 per night). http://www.comfortinn.com/ires/en-US/ht ... otel=MD413
There is also a Sleep Inn and a Red Roof Inn near the Comfort Inn. The prices are similar, but my parents say the rooms are not quite as nice.
There is a Ramada in Rockville off of Rockville Pike Road. (I can't find the link, but it's near the Hilton). It is closer to the NIH than the Comfort Inn. My mom said she met a patient who receives treatment frequently, so he was able to strike up an $89 per night deal with the manager. Just speak to whomever is in charge and explain your circumstances. They might be willing to do the same for you.
Rooms will probably be hard to come by these days because of the cherry blossom festival. Also, this is the time of year when many high school history students take their annual field trips to Washington DC.
If your family member is an inpatient, ask a social worker at the NIH if there is space available at the family lodge. It is pretty and clean and right across the street from the clinical center. They have a full kitchen downstairs where you can store and cook your own food. They also have a library, a business center, a small fitness center, and laundry facilities. The place has a real community feel to it, since everyone there has a loved one undergoing testing/treatment. And it's totally free! http://clinicalcenter.nih.gov/familylodge/
I hope this information is helpful.
C.J.