Hi Mary,
Well if Jake and the Neverland Pirates are his favorite, you have to go to Disney's Hollywood Studios. You will want to see
Disney Junior - Live on Stage. Jake may also hang out in Animation Courtyard for pictures and autographs.You will also want to see
Lights, Motors, Action! Extreme Stunt Show with Lighting McQueen. Lighting and Towmater also take pictures as well. This is one day of your vacation.
As for Goofy, you can find him in every park. He has his
Barnstormer roller coaster in Fantasyland of Magic Kingdom. You might need a day or two in Magic Kingdom.
He does jungle adventures in Animal Kingdom and regularly appears at Tusker House for breakfast and pictures in Camp Minnie-Mickey. This is a day as well.
While he is in Epcot, and my children loved Epcot even at four, you may just want to add another day at Magic Kingdom. Animal Kingdom and Hollywood Studios should be well covered in the single day you are there.
Wishing you a magical vacation!
Beth