How should I charge for a stay where I bring dog to a wedding ceremony?

Your profile doesn't show a transportation rate, so you can enter a + cost adjustment when you book to add what seems reasonable for the extra service of transporting the dog to&from the ceremony. Dressing the dog doesn't seem to merit an extra charge (just like you wouldn't charge to place a raincoat, jacket or sweater on a pup if needed.) Even though you expect not to need to watch the dog during the ceremony, you can still count all time with the pup as serviced time. So, if the entire timing is within 24 hours, you may charge 1 night of boarding plus transportation adjustment.

I assume that the dog is staying with you and that you'll have it while the couple is on their honeymoon. What you charge for the additional service of bringing the dog to the wedding really depends on whether this is a first-time or regular client.

I have taken care of a couple of dogs whose owner was getting married. In neither did I have to perform the service you will. However, one was a very regular client, so I gave them two days of free boarding as a wedding present.

If this booking is a one-time only deal, then I would charge a combination of what both Deb and Walt have suggested: a transportation fee and hourly rate.

Boarding does not imply that you are with the dog 24/7.

Since the wedding will take a significant amount of your time I would charge an hourly rate