I don't know about your specific legal circumstances, but the general rule is that the less you say the less you can get caught up in defending what you have said.
In your circumstances I'd keep it as simple as possible - "your lease provides that it can be terminated with 30 days' notice from the next rent due date. Your next rent due date is [ x] and in accordance with your lease this notice terminates your lease on [y]." Then add everything you need to about the return of keys, inspections on leaving and return of deposit, etc., so that your tenant has all the information she needs in that single document and doesn't have any valid complaints about not being told what was required.
You could think about adding something about the positive aspects of a landlord reference that you would give her: eg "I will be happy to provide a reference to any future landlord that you have always paid your rent in full and on time." But don't say anything about parts of a reference that would be negative if you said anything about them.
Good luck.