A little tip for anyone that ends up with the back-up location, due to rain: You can request a location other than a conference room. I know someone who ended up with an inside Swan wedding, due to weather, & they ended up in a hallway, outside of the ballrooms. This sounds terrible, but it is actually a beautiful space. Really pretty rug & lined with windows with views of pretty greenery outside.
We had our ceremony outside (December wedding with only a low risk of rain), but we had several pictures taken in this hallway & it is very pretty, and got some really pretty natural light.
Just wanted to throw that out there. I'm sure if you describe the space to your planner, they will know where it is.