The apartment was exactly as seen in the pictures, towel, and toiletries are provided amongst other household amenities like laundry detergent, dish soap, and kitchen utensils with very clear instructions. Storage area i.e. wardrobe is limited but it's sufficient for our family. The apartment is very cozy. Portable Wi-Fi is provided but please note that there is a max limit maybe around 10 GB only, so if you have a big family, it is best to get the portable Wi-Fi unlimited data at the airport as the nearby telecom shops do not have that. Spring has been very helpful and always respond to our query promptly. A lot of nearby shops e.g. Family Mart, Seven Eleven, Don Quixote, and cafes. 24 hour grocery store is also nearby. For Muslim travelers, there is a halal shop nearby selling halal meat, halal frozen food and groceries. The name of the shop is called the "Holy Heart" (090-60139503/090-98327982)
Getting there is just via one train from Narita Airport T1,2,3 via the Sobu Rapid Line which is so convenient that we do not need to change stations and trains with our big luggages. The Shin-Koiwa station is equipped with escalators and elevators. Only thing is the "5 min walk" to the apartment is not 5 minutes for our family, it is more like a 15-20 minute slow walk to the apartment especially with heavy luggages and shopping bags. Even though the apartment is near the shops, but walking towards the housing areas could be very quite at night. There are bars and small night clubs nearby, so during weekend, the area could get a bit rowdy, but all in all, we still felt safe.
Overall, we really felt it was a very strategic location for our family, very close to Tokyo station which is about 4-5 stops after Shin-Koiwa. But the train can be very crowded during peak hours, if you need to go anywhere towards the Tokyo area early in the morning, please go to the station early.
Hope this will benefit future travelers. Have an enjoyable trip to Japan!