I did the playpen too with her crate inside with the door open, and newspaper in the beginning for peeing. Now my boston figured out how to get out of them, I had two of them. You have a jack so get the tallest one. I ended up in the end buying a top so make sure it is an added feature just in case. These little terriers are good
How bout the peanut butter filled kongs etc... to keep him busy. Terriers are very active, I have two of them, however I must say the jack is the busiest.......