Reception Decorating

We found a venue that we both REALLY REALLY love and see our selves getting married in. It's just perfect.

But... we are limited on decorating. FH is fine with it, but I love decorating. We can't hang anything on the walls or windows because it's the original work and materials before the building was remodeled (Hotel Vandivort, Springfield). So they don't to risk ruining it, which is perfectly understandable. I can't drape anything due to the only thing on the ceiling is the chandeliers. But the room gives its own beauty with the texture of the window sills, lighting, we can control how high or low we want the ceiling and dim the lights whenever.

I'm here to get some help from others on how i can decorate without just a centerpiece? The theme is celestial.