Is she crate trained? If not, would you be willing to go that route for when you have to leave her alone? If you place her in a crate when you are out and she gets to understand that the crate is a safe place (run a search on crate training to get some ideas on making the crate an enjoyable area) she is unlikely to mess in the crate and will not be able to get into trouble by chewing up the house. When you get home, first stop is to get her outside for a pee break at which time you would praise her.
The bitter sprays work well as does a small amount of alum mixed with water (teaspoon in a cup of water), unless you have one of those dogs that doesn't mind the taste of it (when we were training Lucy not to counter surf we tried leaving a piece of alum soaked bread on the edge of the counter, we heard her jump up to grab it and were expecting a spitting sound of her getting the bread out of her mouth only to find her happily eating it
).
Best of luck.
Cheers,
