I've not been to many weddings and so I don't know if transport between the church and venue is expected to be provided by the bride and groom? We could ask people to drive to the church and then to the venue, they can leave their cars there safely over night if they would like to drink and get a taxi home. Most people will be staying a 7-10 minute drive from the venue in the nearest city. We could alternatively hire a bus to transport people from the church to the venue.
What did you do?