A recreation of The Terminal Bar where Dolores worked would have been another eatery, and would have connected to the Red Car Trolley, as seen in the film. There's never been any information on how much of a role Jessica Rabbit would have played if this section of the park was created (merchandise, a costumed character, etc) but it has been said that Roger was going to be included in the original gang (Mickey, Minnie, Pluto, Donald and Goofy) and was being pushed to be as famous and recognizable as Goofy.
(photo left courtesy MartinsVids.net) shows how invested Disney was with Roger Rabbit. The section was to include what might have been the parks first roller coaster, based on the cartoon short Roller Coaster Rabbit. According to a New York Times article:
Movies Provide Themes For Disney World Attractions
February 18, 1990 | By New York Times News Service
Disney's movie division is providing inspiration for a new series of back lot "neighborhoods," rides and restaurants at Disney-MGM Studios in Florida. According to plans for the theme park announced recently, the movie "Who Framed Roger Rabbit?," made by a Disney subsidiary, Touchstone Pictures, will be the source for an area called Roger Rabbit's Hollywood to be built in the mid-1990s.
This will be a kind of Toontown, where-as in the movie-only cartoon characters may live.
Visitors will meet the movie's eponymous cartoon hero, ride a Toontown trolley rocked by flight simulators, hop into Benny the cartoon cab, and careen in overaged Baby Herman's baby buggy through a Toontown hospital.
(photo right via 2719 Hyperion)
Aside from some presence in the early days of the Disney-MGM Studios, Roger Rabbit's Car Toon Spin was a ride created in the Toontown area of Disneyland, and there was a Jessica Rabbit Store that briefly existed in Disney World's Pleasure Island.