I didn't think there was anything in the parks you couldn't use your Disney Dollars on, including park passes. Maybe not UPH because I don't thing they are sold in the parks, they are part of your package, but I bet they would accept them when checking in at your on-site hotel. Im pretty sure they can be used for park hoppers, park hopper pluses, single day tickets- the tickets sold at the parks and at the Disney Stores. (By the way, single day can only be purchased at the park, you can buy the others at the stores). Disney Dollars are cash and should be used as such. I use Disney Dollars a lot, that is how we save for a portion of our trip!