I highly recommend not making roundtrip reservations with SuperShuttle at BWI. Using SuperShuttle to travel from the airport to the downtown hotels works very well, but the reverse does not seem to be the case. Twice, I've been stranded at a hotel: once at the Tremont Plaza and once at the Tremont Hotel. A colleague noted to me that three people at the same meeting, leaving on different days and/or at different times, also were stranded and ended up taking cabs. SuperShuttle reimbursed them, but the trend seems unreliability on the return trip. Alternatively, make your reservations in plenty of time to arrange for a cab or to call SuperShuttle often enough to get them to the hotel.
The Tremont Hotel on Pleasant Street has huge executive traveler suites. I don't know what the regular price is, but the Johns Hopkins meeting rate is quite good. The suites have a full kitchen (stove, microwave, refrigerator, coffee maker, coffee beans and grinder, dishes), an office area, a living room with a TV, a large bathroom with an ironing board and iron, and a large bedroom with another TV. The corporate suites apparently don't have the living room and office area. If you're going to Baltimore and need to meet with people, or if you're going with a group, these suites would be ideal.