ISTC was having trouble with the trainers in mid afternoon (3ish) to about 5, maybe 6ish, give or take a bit.
The Gator, on his regular schedule can normally be found at the end of the bridge leading to the main walky way of Frontierland. Theres a food vendor (Forgot what it is) right by the edge of the water, and theres another bridge that runs parallel to the mainwalk way, he's normally in between the water edge behind that vendor and the second bridge.
When he's on vacation, Ive seen him out by the train bridge, over by that gator near the waters edge (which you can see from the boat) and various other places around the area. Why I even remember the time when he was still just a little guy, Ginger dared him to get into Splash Mountain and pass himself off as one of the singing gators at the end.....
And trust me, these things can find water when every thing and ever one else has failed to find it....Seriously, I believe they dammed the area behind the train bridge and he just went on vacation over there. Not completely sure though.