Hi and welcome to YorkieTalk!
We crate trained our first yorkie, he did fine wihtout a pen. But, we just purchased an x-pen with our new baby and, since my boyfriend and I both work 8 hours a day, it has been a great investment. We have it set up so that she has her crate (with the door removed) with a warm blanket, her food and water, and a litter box in it with her. She has plenty of room to play with her toys during the day and not get poop and pee all over her. When we had her in the crate every day, we'd come home and she was covered, it was just too long to keep her in there cooped up all day.
We are using baby changing table covers in the litter box and right now thay are all over the floor in the pen. After a few days we will take one changing table cover up, and then a few days after that, another one until all she has left is her litter box with a cover/pad in it. We're hoping this will help train her, so far she hasn't caught on to the litter box yet.
Also, she isn't isolated while we are gone. One of our cats often jumps in the pen with her or lies right beside it. Our older yorkie runs free in the living room area and so she has him to keep her company too.
Sorry this was so long, in summary, I think pens are great!
