In my experience with the wave starts (as in, one corral is released in a series of waves a minute or so apart), it still takes roughly an hour after the first release to get through the back of the last corral. And that's where the sweep clock (and Balloon Ladies) start: in the very back of the last corral.
Post-race activities can take as long as you care to spend! I prefer to head out right after, and I'd say it takes maybe 5-10 minutes to get medals, snacks, water, finish photos. If you choose to grab a beer, and/or wait in lines for character pics, you could easily tack on another hour or more. They do close the character pic lines, though, so there's not an indefinite amount of time to get that done.