I took Alex last week on a tour of the surgery center to get him familiar with it on a normal day. I have to say I HIGHLY recommend doing this if you have a young child going through any kind of procedure. The staff was great, and the tour was largely directed at my son and it gave him a sense of the place that I'm sure will be quite disorienting tomorrow. Most facilities, especially those with experience or that cater to pediatrics, offer some sort of tour or orientation. These are usually held after hours and answer far more of your questions than the brief call you receive to set the procedure up.
I know tomorrow will be stressful, and will probably turn out okay, (although fair warning that the next person to say that might get glared at!). But I'm still glad to know that when the going gets tough and my two year old decides that he doesn't want to have his blood pressure taken, doesn't want to let go of mom and dad, or have anything to do with the staff, the orange popsicles in the fridge around the corner are a sure fire motivator! :) And if the popsicle doesn't do it the magic button that opens the doors to the procedure rooms just might.