Is getting a dog walker or sending her to doggy day care very now and then an option?
If digging is her thing you could make her a digging pit. Get an old clam shell and fill it with dirt and sand (it doesn't need to be great quality a few stones is ok) then you can hide a bone in it for her to find and/or a kong and/or any other toy she likes. Kings are a great boredom buster.