Generally no, it's not possible to tour the studios. I had a kind of private tour a few years ago (1999). I have a few pictures from it - I'd have to scan them in, but I can put them online if anyone is interested. Of course I don't remember what half the buildings are now.
They have their own version of the Mann's Chinese Theatre, with the handprints in the cement - with Disney film stars of course. And a courtyard with plaques (some of which have handprints).
I have photos of the outside of the Animation building (I only know because it says "Animation" on it!), and the props storage building, and the outer part of the Walt Disney archives (wasn't allowed to take pictures inside, although I did go inside). Apparently Roy's office was in the hat part of the Animation building.
One of the buildings has a... unique architectural detail to it. Entirely unintentional.
The building is meant to resemble a Greek (Roman?) style, you know the type where there are statues holding up the roof? Well in this one they have the 7 dwarves holding up the roof. There was one unanticipated problem though.
The drarves are rather rotund, so their bellies are on the round side. Unfortunately when it rains the water flows around the circumfrence of the belly and then drains off. The result is that, well, when it rains it apparently looks like they're peeing! Oops!
I seem to recall the commisary was pretty good.