Were you not offered a place in Reed Hall? It's not the Hyatt, but it's a free bed and you will get opportunities to interact with students. Hotels in Baltimore (at least, ones you'd want to stay in) tend to be pricey.
Check out the interview feedback section of this site. The Hopkins interview is known for its "mingling," during which you talk to other applicants and MSIV members of the adcom throughout the day. Many people find this intimidating, but the point is really to see if you have social skills. Having met my classmates, I think Hopkins knows what it's doing--my class is great.
Good luck!
🙂