和朋友一起出去晚餐怎么样?翻译是How about going to for a picnic?么

How about going to have dinner with friend?我错了...是野餐How about going to have a picnic with friends?为什么不用for？因为就没有谓语了，for是介词如果用for的话，就得把to去掉，还得加上with friends