Before you go on the trip, I strongly recommend that you prepare questions. I had a hard time thinking of them at Rice, and I regret it. Be sure to ask about the workload. Try to get the perspective of several majors. Also, ask about the dorm policies.
Colleges have different styles of dorms, and assign roommates differently.
Find information on sports or arts or any particular extracurriculars that interest you. If your dorm host does not know about it, try to find someone who does. Ask teachers about the difficulty of their courses and the workload if you can. This information is especially valuable from teachers in your areas of interest. Inquire into any traditions that make the school unique.