If your clerkship is in Bethesda you will possibly be staying the Navy lodge on base. If there are no rooms available you may be staying in Bethesda which is one Metro stop from the Base.
Since you stated you have not been to ODS the proper attire would be slacks, shirt and tie at a minimum.
Your schedule kind of depends what department you plan to complete your residency through. Typically the normal work day is 0700/0730 - 1530/1600ish. The evenings are your to do what you want and you are free over the weekends - you can take the Metro into DC and see the sights or whatever.
If you are interested in a particular program I would make that clear when scheduling your clerkship or you can also ask to rotate through multiple/all of the residencies - 1 or 2 days per program, etc. You will mostly be hanging out within the department and tagging along with residents. It's good to get a perspective from the residents as the programs can change significantly depending on staff. Just something to think about. Best of luck.
