Depends what GPS you use, but I can tell you that my Magellan RoadMate (which doesn't accept outside POI files) was able to find Caribbean Beach, Animal Kingdom Lodge, and the Dolphin perfectly. I usually don't drive around Disney, especially not to the parks, but my last trip I had a conference there so I was off-site a bit.
I would recommend putting in the name of the park or hotel where the restaurant is located, then when you actually reach the park or hotel, following the signage to reach the actual restaurant. Rather than trying to get the GPS to take you all the way to the restaurant.