It sounds like it could be fun- the part of her reading it aloud- that would turn me on and be difficult, therefore also a good learning experience- to learn to be able to express my needs, wants.
In thinking of this scenario, have you considered how it would best help her to grow and get back into this lifestyle with you? Depending on her personality, it may or may not be the best thing.
I have to add I was a bit confused about the "Everything that is not in this can still be asked and if declined will result in a consequence ranging from physical pain to another request that is different but maybe harder to perform."- why would you punish her or give her a more difficult task if she asks something and you decline it? b/c she didn't think of it at the time of the letter... or... ?... i would just like to understand that part.
Overall, though, it sounds like a good idea.
If you go through with it this way, i would be curious to know how it goes.