putting him in the crate, at OTHER times now and then may help.

You do have maintain "alpha" status in your house. If you coddle this dog too much, he will try to become alpha and may be afraid of being so. Growling, biting/nipping, and excessive barking, and even attacking visitors may result, when a non-alpha dog assumes alpha position in the home.

If you get NatGeo channel on TV, Cesar Milan has many shows on there that address adopted dogs, who become "alpha" because loving owners "baby" them too much based on the adoption from prior abuse. He contends that the dog lives in the "now" most of the time, and the past fades for the most part. (The Dog Whisperer).

Cesar contends that giving praise or treats at the "wrong" time also creates problems. So I would not give treats so much. Making a trail to the crate is perhaps too much?

The dog needs to learn that the crate is a safe place. By putting him in there at other times randomly, he will learn you are not always leaving and associate the crate with abandonment.