Have an open itinerary: have a plan for the things that are harder to do spontaneously (restaurant reservations, show tickets, coupons with date/time restrictions), but don't plan your day down to the hour.
I've had a detailed itinerary and we never get everything done and we tend to feel more stressed to meet deadlines/appointments. I've also gone without a plan and struggled to get into a restaurant without reservations, found shows are sold out and felt we were all just stumbling around from place to place with no semblance of order.
You know how it is when you do things with a group? First, Buffy has to use the restroom so you all wait a few minutes for her. Just seconds before Buffy gets back, Todd decides to play $20 in megabucks and goes on a mini-roll before tapping out. However, Gertrude now has to pee, but can hold it until the next set of restrooms, where we all wait again. But wait, doesn't that burger look good? Wilbur thinks so and he's now in a line 12 people deep to get one. Tara is whining because her feet hurt so bad and her 4 inch heels that look so sexy are now making her walk like a giraffe with a broken ankle. Bubba just puked in the nearest trash can, but wait, he just ordered another beer so he's good to go. Okay, 100 more yards and Cinthia (with an i, not y) and Tyrone have disappeared so we all Scooby-Doo (think about it and you'll get the reference) in search of them. By the time we all get back together we just ended our first 6 hours in town. Can't wait for the thrills tomorrow. Maybe we'll actually leave the casino if we all just work together.
So it is good to have a plan, but make it flexible and enjoy!
ebbinns