How did the play date in the park go?
To touch on his marking specifically, here's how we always dealt with it:
He would spend a lot of time outside so it would give him plenty of oppotunity to go potty outside and not even on the pads inside, but we also walked him in the morning and he would mark so much stuff that he had no pee left!!
Then when he went in the house and went around, he had nothing left to mark with.
He has always been very difficult to train, we tried clickers, treats, constant supervision, etc, and he is tricky. Karma, on the other hand, picks up on words and signals very quickly. He may respond well to a class, since we never had the money to send them, we did training ourselves.
Let me know how it works out.....