First off, how awesome of you. Second, I've never had experience training a rescued dog, but can I just say (while I do completely totally understand why you wouldn't want to crate him because of his past...) dogs do NOT think in the past or the future. Their minds are in the now. And I think a lot of people will rescue a dog, spoil and baby it because of the past life he had and then they become out of control and hard to handle and train because they know they can get away with everything. So make sure rules still exist to him. But personally, I wouldn't crate him either
Just trying to say to treat him like a normal dog and give him the same rules and boundaries you would a little puppy. Congrats on your new dog!