Wow, I feel like we're in the same boat!
I pottytrained my mini dachshund as a 10-month old puppy & I'm trying the same things with my foster Yorkie, Sophie. I've had Sophie for 8 days & I found her wandering in a neighborhood.
When I can't watch her, she's crated or gated in the kitchen. When she's with me, she's on my lap or on an "umbilical cord", i.e. her leash with the other end on my ankle.
I've caught her in the act of pottying inside the house ONCE & we rushed outside...Sophie then decided that she wasn't in the mood anymore! UGHHHH!
I'm also trying treats for each potty outside, along with the best verbal praise possible!
