Hello Kelley, and welcome aboard! 8)
A dark cloth would definitely help, even more so if you have lights around you...
Jupiter is low in the sky at that time, and that won't help you much if you plan on pushing magnification..., as you'll normally want to do that when it is at the highest setting or close...
Also, you should know that The Seeing will affect planetary viewing very much, and most nights you'll be able to stay around 150x or so, but not so many you'll be able to go over 200x unless The Seeing is very good...
You should be able to see two brown bands across the planet (in Jupiter), and maybe some more detail if the conditions are GOOD...
You scope should give you nice views of Clusters..., are you using any Star Chart? any Software to help you out?
I'm sure you'll enjoy the Observatory visit and the Star party... come back and let us know how it all went...

Clear skies! 8)