Welcome to the board, newfiek9! Nice to see another Newfoundlander around here
Good for you for taking in this dog and giving her a loving home. I don't have a lot of experience in training an older dog, but it seems as though what you're doing is right on track. If she pees in the house and you notice it later, you can't correct her because she won't understand the problem. If you catch her in the act, I would give a sharp "no" and put her straight outdoors. The crate is also a useful tool and you're right that it will make her feel more secure. Every time you take her out of the crate, put her outdoors and tell her to go pee or whatever. My mother-in-law prefers "do your dirt." Hahaha. Give her a treat when she does it. She'll quickly catch on, I'm sure.
Someone with a bit more experience will come along shortly, I'm sure, to give you some more concrete tips!
Good luck & keep us updated
Also.... we love pics of pets around here!! Feel free to post as many as you would like!