About the Caduceus and ships like her...she will ALWAYS be carrying patients, since she is a mobile hospital. In whatever sector she is moving around in, Starfleet and Federation worlds and outposts will no doubt count on her for critical care needs that are not met by the 'regular' medical services. She has all the facilities in medicine of a large starbase, and therefor would be the alternative for those for whom a starbase is far away.

Since, for some worlds, she is the ONLY effective option for medical care and especially for treatment of new and previously unseen ailments, the internal ambulance services of the ship will be kept busy, supported also by civilian and other Starfleet shipping, keeping a flow of patients moving to and from the ship.

While the ship does not maintain a large civilian CREW, she is likely to have some guest quarters for civilians who come in to the ship to be with critically ill patients, and to train in the medical and services areas in which the ship is well prepared. While the Caduceus is not a teaching hospital, it does maintain highly adequate facilities for in-person, media-supported, and holographic interactive instruction. It even has a small computer core of its own, dedicated to the clinical and intervention practices for medical care for all known species. And it collects data, refines knowledge, and communicates this, throughout the UFP and even to non-member species.

The MASH unit within Starfleet becomes, by its very nature, a special kind of goodwill ambassador, speading healing and knowledge throughout any sector in which the ship operates. Some have suggested that the research activities of such a ship take a secondary role to those of the clinical side. This is not really the case, as the scientists and medical specialists supporting care are often beleagured with requests for knowledge, and for requests that require research or coodination of clinical and theoretical problems in other facilities throughout the UFP.

Special thanks to Russell Vanneman for providing this information.