Because the hospitalist is a relatively new career in the U.S., MOST university-based categorical IM programs will prepare you well for and provide mentorship for fellowship applications.
From my experience on the interview trail, very few categorical programs have hospitalist "tracks" (U of Colorado, UPMC come to mind).
If you want to obtain a fellowship, highly rank university-based programs that offer fellowships in your desired field. That is the best way to gain connections, meaningful letters of recommendation, learn about the field, etc.
(Of course graduates of community programs can obtain fellowships but it is more difficult)
