I agree that hands-off is the best way to go.
When DD#1 was a freshman, we went to the orientation . . . there was an overview session with parents and students. We said good-bye, then the students went one place (for the rest of the weekend) and the parents went elsewhere for the rest of the afternoon.
I found the orientation to be informative and interesting since I never went to college and really didn't have a clue. A lot of the parents' orientation was geared around student safety and services that were offered (counseling, transportation, etc.)
A lot of DD#1's school independence started in HS. I didn't have to ask about grades/tests/homework, she was a good student and took care of this by herself. School was simply a matter of everyday conversation "How was your day?" type of thing.
So when she went off to college, I was confident in her abilities and knew that I wouldn't have to nag or be nosey. We'd talk on the phone at least once a week, main topic being her schooling because, well, that was her life.
I didn't grill her about her grades and I like to hope to think that when I asked her "How's that icky TA situation going?" she didn't feel like she had to give me a report or that I was being too involved (helicopterish) in her college life. It was just a point of interest, something to talk about.
I like to think that the thing I did best was offer support/encouragement.
DD#1: "Mommmaaaa! I got a D on that test! I studied so hard!"
Me: "Sweetheart, I know you did your best. A D is a whole lot better than an F! Maybe ask your professor if there is any make-up type of work or extra credit something that you could do?"
DD#1: "He gave us a list at the beginning of the semester. I should look at that, huh."
Me: "Yeah, maybe. It's your life. What do you think you should do?"
Is that being too involved, too hands-on?
I'd like to point out that I never coached her on what classes to take, what she should or shouldn't major in, how to sign up for the next year's schedule, which dorm she should live in . . . she figured all of that out on her own.
Most importantly, DD#1 will be a SR next fall and having her home this summer is such a joy in my heart. She has grown to be a very responsible, independent, likeable young lady. She has her life's dream ducks all in a row and achieved this with no helicopter coaching from me.
It is amazing how much she's grown in the last 3 years. I am very proud of her.