The ExPen idea has been scrapped. I came home at lunch to be greeted by my 3 favorite puppies. Don't know how she did it, but the doors were secure & the opening was hinged. She must have slipped underneath ~sigh~. So, she's back in the crate where she should have started. I'm keeping this to myself to avoid a few "I told you so's...".
As of yesterday, the crate worked fine. At first I thought she had held it the entire time, but came to find she peed on her blanket, rather than the papers. Let's hope we've turned a corner. I've been working w/ her a little every night getting used to the crate. She's still not comfortable chewing when in the crate so we need to work on that too.