The book has been working really well for me so far. If you do decide to crate them again, see if it helps having them near your bed. Mine will freak out if he isn't in the same room as my husband and I. It gives him his space and gives us ours. As far as the treat goes, I give mine one of those Nylabones and a few of his other little toys and it seems to keep him occupied.
That's about as much advice as I have
Good luck
