My family stayed at Cherry Hill Park for over a month and had a wonderful experience. Everyone who works at the park is friendly and helpful. The pool and hot tub were a big hit with our kids. Laundry facilities are great, two parks for kids to play, basketball court, etc. A metro bus will take you to the metro station which is very close by, or if you have a car you can park at the station for $4.50 during the week or free on the weekends. If you have more than a couple of people in your party it saves a good amount to do that. There is a daily presentation on using the metro and the DC tours that was very helpful.
My family stayed at Mylan Park for a month in March-April 2014. The employees were very helpful and easy to work with. Just go in during regular hours on a weekday and someone should be able to take your payment. Email response before our visit was hit or miss. We were unsure of our dates and they were very flexible - we made an initial payment, then a second payment once we knew how many nights we'd be there. The discount for multiple nights was $20/night. There is nothing special here; it's just a giant parking lot with hookups. It was great for my kids to ride bikes and scooters. I highly recommend Mylan Park if you need a place to stay in Morgantown. The location is very convenient to stores and restaurants.