婚房 honeymoon room(房间) 或 honeymoon apartment(套房) 或 honeymoon house(房子)
内部装修: interior decoration
具体用哪个词态和词组,可参考: ~~非常不错而完整的回答
"装修房子"用英语怎么说?
http://zhidao.baidu.com/question/12233195.html?fr=qrl
new department for marriage
wedding room
bridegroom decoration / bridegroom improvement / bridal chamber improvement 洞房装修