Yes, it is a good family hotel. They only have 2 washing machines and 2 dryers so if you plan to do laundry, keep that in mind.
It is approximately 5 minutes walk from the hotel to the gates to either DL or DCA.
The breakfast is next door and upstairs in Captain Kidd's restaurant. They serve fruit, 3 or 4 different types of cereals, hard boiled eggs, toast, bagels, danishes, donuts. It's certainly enough to get your day started sufficiently.
Don't know about any coupons or codes for savings.
I stay here every time I go. Have stayed at the Grand Californian (huge waste of money and the walk was soooooo long), the Candy Cane (great hotel, great breakfast, they do have their own shuttle to/from DL and DCA) and have stayed at the Carousel. The Carousel is sometimes a little cheaper than the BWPPI. I just stay at the BWPPI because it's the closest, it's a nice hotel (parking is difficult -- too few spaces and the spaces are too small), it has the free brealfast, and it's reasonably priced.
Hope this helps.