As someone else who lives here posted a few days ago (and I agree), wash park honestly would not need to be "searched" - it's a relatively smaller, open park. Well, not so much small as open - every part of that park is used on a daily basis by hundreds of people...runners, bikers, walkers, people playing games or just hanging out in the park. There are trees here and there but no big wooded area or anything. Basically, it's a flat city park with a path around the perimeter and sidewalks throughout, heavily used by LOTS of people in the surrounding neighborhood for recreation. The lakes are shallow and there are paths (and benches) that go around them as well. In short, if he was in wash park he would've been found by now. Re: Cherry Creek trail (or closer to that area, the Platte River trail), it's certainly possible. However, it's unlikely that he would have ended up in there by accident, IMO - both are bordered by paths and, for the most part, are accessed by going down specific access ramps. It's not like you're walking around in the city and would stumble upon a river crossing, especially in that area.
The water along the cherry creek trail is quite shallow for much of that part. The Platte is a little deeper at parts, especially to the south of there, and is relatively fast moving. However, if the theory is that he was drunk and accidentally stumbled in there...I don't see it as likely.
