One of the staples of any theme park experience is the food, and Great Adventure aimed to please with three major restaurants and several smaller food facilities including Fountain Cafe which was a food stand located near the center of the park at the Fountain.

The Fountain Cafe was one of the small restaurants built in the park when it opened in 1974, selling snacks and drinks. The location beside the Fountain and the Gazebo was an ideal place to sit and rest under the trees and enjoy the music on an afternoon.

With the relocation of the park's entrance to the Fountain area in 1976, the restaurant became even more popular with guests entering and exiting the park stopping for a snack after or before their long drive.
Restaurant Names Through the Years

1974-1975:  Fountain Cafe

1976-1977:  Snack Stand

1978:  Fountain Hamburgers

1979-2006:  Great American Hamburgers

2007-Present:  Johnny Rockets-
The Original Hamburger
For the 1979 season the Fountain Cafe took on the name Great American Hamburgers which better reflected the patriotic theme of the overall entrance plaza.  That name would remain the same until the end of 2006.

For the 2007 season the cafe was given a major makeover becoming the first of the park's Johnny Rockets locations. What had been a somewhat colonial themed structure was made over in Johnny Rockets style with a pseudo diner look.  The makeover took place over the first few weeks of the 2007 season with the interior and exterior of the building getting remade.
The patio area next to the restaurant was updated with red Johnny Rockets umbrellas and matching trash cans. The exterior of the building was fitted with large neon signs making the restaurant more visible from all around the Fountain. 
Johnny Rockets was immediately a big success in the park, drawing huge crowds of guests for the name brand food offering. The burgers, fries, onion rings and milk shakes were a hit with the teenage crowds who knew the brand from their local malls.
The success of the first Johnny Rockets in the park lead to the addition of several more locations inside the theme park and even inside Six Flags Hurricane Harbor in the following seasons.

Some of the other locations in the park offered a more limited menu with just shakes and fries, while two others offered the same menu options as the Fountain location, but none were as popular. Like anything else in real estate and retail it always comes down to location, location, location.