It took us ages to train ours to be left so you have our symapathy.
Jon started by leaving them by short periods during the day- just walking round the block. To get them used to the idea we go out but we come back. Now we can leave them, but anything that's around gets played with. And it is difficult to clear everything away totally so we tend to exhaust them then shut them in the hall with their toys but all the doors closed. They bark when they hear the car and I'm worried about upsetting our neighbours (more than usual) and the hall is away from the connecting wall.
Recently Jon's been ill, so hasn't been out a lot and our 19 year old is back from Uni, so they aren't being left much. Means they aren't destroying things but we'll be back to square one when the autumn comes and they are left home alone.
Cages aren't an option for ours as Bob's not cage trained and hates it- howled the place down when we tried to get him in a cage Steve lent us at the start. Hopefully Daisy will take to the cage and make it her den.
Good luck
PS Why not ring Michelle during the day? Her number is on the rescue home page