I do have to disagree that cats will live a short, happy life with outdoor access - Ginger lived for 11 years being one street behind a busy main road, and 3 of those he was living rough. The 18 and 2 15yo's here have all had outdoor access in previous homes, although I dont know what the area's were like.
As others have said Kirst, it really does depend on the rescue - some have blanket policies, some don't. If there is a cat proofed garden, i would be happy to home to it, and have homed to where other rescues wouldnt because I took the back of the house into consideration, rather than just looking at the front.