Catio functional! Toast, my outdoor-lovin' guy, spends about 80% of his time out there, and has mostly figured out the cat door, although if I'm there he meows to be let in even though he's let himself back in several times. One of the unforeseen hazards however, is that he keeps catching things and bringing them inside - nothing like a screeching cicada in the hallway at 2am to get you out of bed fast! Also one big dead mouse and one partially eaten small mouse. Lovely.
I had a ramp system kind of jury-rigged with some boards and bricks, but mom got all excited and ran out and bought me nice sturdy wire closet shelving and some outdoor carpet to put on top of it, and my brother came over and helped attach everything with brackets and things, and now even the not-so-agile Gandalf can make his way around everywhere. He's still scared of the cat door, although I've found him outside on his own a few times now - I always have to hold it open for him to come back in. I held Bones up to the cat door and held it open to see if she'd be interested, and as expected she was utterly horrified and ran away to her nice safe lurking basement. I locked the cat door while we were switching out the ramps, and in one of the photos Toast is pressing his head against it, very frustrated that he can't get it open to go to his happy fun place, lol.
Still needs some work right around where it meets up with the house to make it raccoon-proof, so raccoon baby has only been out for supervised playtime, but she's all over it like a fish to water, so to speak ^^
Here's some pics - I think I've got the permissions set right: Catio/Raccoonio Flickr album