If you're lucky they'll respond to your locator calls by gobbling. In my experience they respond to shock calling the best at dawn, but they will respond at any time of the day if you catch them in the right mood. Another good time to try the locator calls is at dusk. If you can get a gobbler to answer just before dark you can be pretty sure that he will be spending the night in a tree nearby and you can return in the morning to greet him.
Just remember, Roosted doesn't necessarily mean Roasted.