Gus Hernandez JR has an excellent article on church and campus ministries working together. One practical element to this that many seem to miss is that a strong campus ministry benefits the church even more.
Some churches cooperate in providing some money and being supportive in a visual way by attending events. But, they schedule similar events to the campus ministry or tie students up so much they must choose one or the other. If a church is partnering with the campus ministry, they need to ask, "How does this event or emphasis affect the campus ministry?". Many are cooperative but then do things that harm the campus ministry....cooperation means considering how my actions help, hurt or affect the other. The campus ministry also must ask that question. But, each church must also realize that campus ministries are trying to benefit more than just one church! That makes their decisions tougher.
The stronger a campus ministry is...the more it can help a cooperating church.