I have a really good lease contract, but can't find the e-version of it. Basically your lease should include exactly what type of riding is permitted, something like "jumps not to exceed 2'6", no trailering off property", whatever you agree to. You would need a clause stating that both of you acknowledge the horse is currently sound for work and put in writing who is to pay for vet bills should that change. Most leasers pay 1/2 of shoeing costs, owners pick up full price of routine shots and care. Terms of contract, ie how many rides a week. Also be clear on whether she can use her own tack of if she needs to ride in your saddle. If she does use her own saddle, make sure it fits before hand. Lastly, make sure you have an out clause. Usually you give 30 days notice of termination. Can't think of anything else right now. Don't worry about coming off like a control freak in the beginning. It's your horse. You can always ease up if she turns out to be a great fit for your horse.
You just have to see your distance...you don't have to like it.