In a way, I both loved and hated seeing these photos. I have many fond memories of going to River Country when I was a child and have always wondered about the sudden "disappearance" of the park. I know it was closed when we were there in Nov. 2001, but they still had the purple signs up with arrows directing guests how to get there on the various roads throughout WDW.
On my last trip, in Dec. 2008, I took the Ft. Wilderness Segway tour and was able (thanks to some tour guides who decided to "look the other way") to take a couple of quick pics through the fence and a few over the fence when my friend climbed up on one of the huge rocks. It was just a view of the pool with the tall slides that dropped off into it, but it was very creepy. It, however, looked much better than the rest of the place now does, apparently. Sure, the pool looked like a bit like hell, but it really just looked like a pool that had been through a rough winter and needed some prep work before reopening. There was even a freshly-painted RC trash can just outside the fence!
In talking to a cast member later that night, I found out that the reason that the park was never demolished was because Disney had had plans to refurb it and reopen it. However, they found that there's a harmful bacteria present in Bay Lake that (obviously) made it be present in the non-pool swimming areas of RC, too. It can make humans very sick, and as of right now there's no way to control it without doing severe damage to the environment, so that's why the park has never reopened.
...and here's a "live" pic:
I'm the one with the pigtails climbing out of the water, and my brother's the one taking the flying leap.
I miss that place.