Separate the wedding party from guest movement.
The couple and wedding party may need an earlier vehicle for photos, while guests need hotel-to-venue transportation. Treat those as separate movements even when one company handles both.
Count passengers for each trip instead of using one total guest number.
Protect the ceremony start.
Work backward from the latest acceptable guest arrival. Add boarding, loading, traffic and a buffer rather than scheduling the shuttle to arrive at the ceremony time.
If the venue has one narrow entrance, staggered trips may need extra turnaround time.
Make the last ride as clear as the first.
Decide whether the reception has one final departure or several return waves. Tell guests which hotels or drop-off points each ride serves.
Before the wedding, confirm venue entrances, contact numbers and any items traveling with the wedding party.