The way a parish pilgrimage goes wrong is familiar. A generous pastor says yes, and within a month he is holding deposit checks, fielding questions about single supplements, chasing passport numbers and explaining airline schedule changes after the Sunday Masses. By the time the group leaves he has done the work of a travel agency and has little left for the work of a priest.
So settle the division of labor at the start. The operator should take registration, payment, rooming, flights, travel documents, supplier contracts, insurance questions and the inevitable last-minute changes, and should answer pilgrims' questions directly. Ask to see the written terms first, including what is expected of you and how your own place is paid for. A priest should not be asked to collect money or sell anything.
What stays with the priest is what only he can do. He sets the spiritual focus, prepares his people in the months before departure, and brings them home. He also arranges his own celebret, the letter from his bishop or superior that shrines ask of visiting celebrants, and gives the operator his name early, because shrines such as Fátima ask for the priest's name when a group registers.
Promotion need not be heavy either. A short announcement at Mass, a bulletin notice and one link to a page where parishioners can read the details and register are usually enough, repeated over several weeks. Bold Pilgrim is built on this division: the logistics come to us, and the priest shares a link.