If your park is filthy and you already bought loads of handymen, try looking for them near the back of your park. Mine were all bunched up there doing nothing or mowing the grass.
When your adviser says that a guest is stuck somewhere in the park, that's easy to solve. It's just like people zoo.Look at the top screen for a dot that's blinking red and yellow. Then go to that area. You'll see that the guest is stuck because it can't get pass through the queue or because when the ride exploded, the rocks blocked its way or even both. When queue problem or both, just erase the queue.
PS: I keep them sometimes then sometimes I don't let them free.