We had a 4:50 reservation and were in our seats, had ordered and had our drinks and appetizers by the time the parade went by last (around 5:20 or 5:30). They had seated us in the room which has the patio which overlooks the parade so you may want to put a request in your reservation to try to get that room - you can still go watch but you may not know when to go unless your server comes and gets you. In our case, our server opened up the patio doors seconds before the parade passed by. So 5pm should be fine but 4:50 was perfect for us. It's really fun watching from up there because the performers know to look up there and wave to us. Plus you get an up close view of some of the taller floats.
When we went no one was sitting on the patio - everyone was inside. If you are going during the warmer months you may want a break from the heat. We sure did.