On July 7th, JHU Transportation announced the new Keswick-Homewood-Eastern-JHMI shuttle to start on July 11th. This shuttle is a result of the need to connect the new Hopkins Keswick facility to the other campuses, and the shuttle also replaces the previous Homewood-Eastern and Eastern-JHMI shuttles. Service runs every 30 minutes from each end, Monday through Friday 8:00am-6:00pm. Before 8:00am, the memo indicates: "four Eastern departures are scheduled to arrive at MSEL and Mason Hall" although no other information is provided about that schedule.
See the Homewood Parking and Transportation website for details on stops and schedules.
For Homewood students, which I assume would also be able to take the shuttle, this effectively runs from a location near the Rotunda mall to Mason Hall to JHMI. It could provide an alternate way of getting between JHMI and Homewood campuses, especially for students that have classes on the southwest part of campus (Clark, Hodson, CSEB/Hackerman). In addition, those interested in heading to the Rotunda directly from JHMI or Homewood after class or research might be able to use this shuttle. The shuttle also stops at Charles Commons but only by request. However, it is probably better to use the existing Homewood-Peabody-JHMI shuttle to go to and from Commons since that runs more frequently.