arizonared makes some good points regarding the quality/quantity of time spent with the recruit.
Junior has been to several schools, at invitation of coach - some where cattle calls. 3 were "personal". Individual tour of school and facilites, one on one with the coach and assistants, etc are good signs. One coach, with a good reputation told Junior: "we are going after 5 guys this year - you are one of them." This was after we had just spent 5.5 hours with him - me, Junior, and Coach. Follow up emails repeated same. This is a good indication. You obviously won't get this everywhere, but it told us something. Asking some of the players what the previous season's tryout were like also could help give you an idea.