The logistics are handled by the outreach arm of each of the 3 NP Labs and their professional lobbying organization. They make all the appointments and make up the schedule, and organize the briefing before the event. They also provide all the materials needed for the visit, such as the talking points and the ask for the year. Typically, participants reach DC the night before the event (a block of rooms will be reserved for this event) and there is an initial gathering over dinner and then there is a briefing meeting on the morning of the event. During this briefing the organizers will have your personal schedule which should include visiting the senators from your state and the representative from your district. You would be the lead for those visits, and there will be others users, not from your state, who will accompany you (usually 3-4 others) to support you. And you will be the supporting person on a few other visits to representatives from other states. Typically you would have about 5 visits throughout the day and each visit lasts less than 30 minutes.
For the 2015 NP Day the block of hotel rooms are being reserved at the HYATT ARLINGTON, 1325 WILSON BLVD, ARLINGTON VA 22209, T: 703.908.4671 F: 703.908.4659 E: firstname.lastname@example.org, www.arlington.hyatt.com The rate will be $105 for the night and 13% tax.
A few slides on how to prepare for the NP day https://wiki.jlab.org/cugwiki/index.php/File:Doucette-Nuclear-Physics-Hill-Day-Prep-3-17-15-2.pdf