Where to play away from home

I have an idea for a scene that I'd like to set up for my sub and am having trouble figuring out where I can do it. She likes the idea that she doesn't k ow what I'm going to do next, so I want to play off that with the following scene.

She gets home knowing I've left something for her and finds an instruction sheet on top of 3 ziplocked bags with sealed envelopes inside. Each envelope will have been scented: one with my body wash, one with another body wash I don't mind, and one that neither of us like. She is to open only one envelope and follow the instructions. Each card will have different instructions that will lead her to a place she had never been where she will find toys laid out. The instructions will tell her how to tie erased while I stay out of sight (but perhaps watch from a camera). I would like to have new toys there so she can't tell whether or not she has selected the right card or not until I arrive. The right guess will earn a very pleasurable bondage session. The middle will entail a punishment scene (perhaps whipping on a saint Andrews cross) followed by a pleasurable experience. The one we both hate will result in a harder punisent (perhaps a wooden pony) followed by a recovery scene.

Any ideas how to find a place to do this? I need it to be safe and probably no one to see her there to prevent her from backing out.

(Also, since she likes to be totally submissive I will leave a dice to choose for her in case she would rather have no say in what happens.)