help with rehearsal????

we are getting married at the hall, we are using reverend Callahan, anyone use him? anyone get married at the NRC?? we were wondering if we need to have a rehearsal?? we plan on having the dinner and telling everyone who they are walking with and in what order, but we are not going to the hall. do we need to have him there at the place we are having the dinner? will the hall direct us the day of w/o at bunch of confusion?? anything else i should know to tell the BP at the rehearsal?? help!! it's getting so close and i'm starting to stress over minor detail!!