Please see the schedule for the dress code for the various events.
For Wedding events park admission is not necessary, if you do plan on going to the parks on the same day as the wedding events then it is necessary.
There is parking for the ceremony at the Wedding Pavilion at the Grand Floridian. There will be transportation back to the parking lot from the reception.
If you are staying on a Disney Resort take Disney transportation to the Magic Kingdom and then board the Resort Monorail to the Grand Floridian Resort.