I highly recommend putting the crate in your bedroom to allow puppy to sleep in there at night. Luna (my pup) sleeps in her crate in the bedroom, and I feel it's what got her used to the crate much quicker. She didn't even whine the first night she was home, because we were near.
Are you unable to get home every 3 hours or so to let your pup out to go potty? I am wondering why you are using a crate inside a pen... Crate training will go quicker if you can actually put puppy in the crate rather than allowing them to use pee pads in the crate area. I am wary of leaving a puppy with pee pads... simply because many of them choose to eat the pads. The pads are made of material that swells when it comes in contact with liquid (to be more absorbent) and it will do the same thing in puppy's tummy.