You could park at the boardwalk and walk over. It would be closer than Hollywood Studios.
You could do, but you shouldn't.
Parking at the Boardwalk is only for people using the Boardwalk for dining etc if they are not staying at those resorts.
Parking for Epcot is provided at the main entrance. Using the Hollywood Studios parking and walking or taking the boat to the International Gateway would be an appropriate alternative.
ford family