Like everyone else....it's too early to start worrying about this now. Actually, if they are saying rain already, there's a good chance it will actually turn out to be dry when the day finally gets here.

However, if it does rain, for you to cross that dirt road, could you maybe find some kind of cheap runner (rug) that you could throw down right before you cross so you don't get shoes and dress all muddy? Too bad you don't have to cross it after the wedding, then Andy could just carry you. Good practice for carrying you across the threshold.