The Central Gully of the Fortress has a very different character than the Right-side Gully. Whereas the Right-side is massive and towering (with 3 huge peaks looming overhead) as well as steep and loose, the Central Gully is low-angle and comfortable. The Central Gully is actually quite pretty. The routes in the Central Gully are also more moderate in nature.
The best way to access the Central Gully is to climb Footprints and then walk uphill to the base of Snickerdoodle or Blue In Green.
To move from the top of Snickerdoodle over to the base of Rational Expectations & Magali's Arete, one must rappel about 30 feet, step across a chimney and then scramble for a few feet. It is actually easier to rappel to the base of Snickerdoodle and then climb Blue In Green to reach the start of Rational Expectations & Magali's Arete.
For a detailed photo of the Central Gully that includes climbing and rappel routes, click here
On April 1, Jesse Groves and I climbed an awesome circuit that began in the Central Gully and finished in the Right-Side Gully. We started on Footprints, at the base of the Central Gully, and climbed 4 pitches to the top of Seven Steps (with one rappel/scramble to link Snickerdoodle to Rational Expectations). From the summit of Seven Steps, we rappelled West into the Right-Side Gully by descending to the base of Adaptive Expectations.
This circuit was an awesome tour of the Fortress and is highly recommended to anyone. For a photo/topo, click here
UPDATE: My recommendation has been superseded by the completion of Spontaneous Order which was made possible by Romain's excellent route "Blue In Green."