My apartment is beautifully located right in the city centre at one of the poshest canals of Utrecht.
A queen-size double bed should host 2 people. A double inflatable airbed or the large couch should host another 2 people.
It's a quiet and friendly neighborhood but at walking distance from all the shops, restaurants, bars and clubs in Utrecht.
The central station is 15 minutes walking distance. From there a train will take you to Amsterdam in 30 minutes.