I think a 7:30 PS will be too early if you are going to use Disney transportation. There are a few early buses (starting at 7:00) that circulate through the resorts to take guests to the parks for character breakfasts there. They drop you at the parks, not other resorts. Therefore, you would have to take one of these breakfast buses to MK, then transfer to the resort monorail to get to the Poly. This could take up to an hour.