She could slowly get Leather used to the crate while she is home and Leather can see her. Then she can disappear out of Leather's view for short periods, gradually extending the length of time she's in another room.

I would be worried about leaving Leather outside because of what you say about her climbing the gate

Have you tried Buster Cubes? Its a thinking toy like the kong and should keep Leather busy.

http://www.bustercube.com/