I see that this is on top of a hotel...does this mean we need to be a part of the hotel or can anyone go to the bar? Also, when would be a good time to actually go? I keep seeing people say that it's always packed.

You can go anytime, no need to be hotel guest. It can get crowded but we never had a problem getting served. A must for cocktails at sunset!

Go for the sunset it is awesome. Probably have to park in a nearby parking garage, parking is a problem.

No you don't have to be A guest at the hotel. Open to the public. Any time is a great time to go. Beautiful scene and good drinks, food, great hospitality as well.