Now, Medicare has a website that allows one to compare Part D (Rx) plans in your area. I haven't been there in a few years, but I recall it being a big pain in the neck. Once you work your (her) way through it, it does allow you to compare plans. Note that each plan has its own formulary, deductable, and copays. Do not sign with a company that doesn't cover her prescriptions. Don't waste your time trying to avoid that donut hole. You're pretty much stuck with it.
Plan F for medical is a good one. They all offer the same coverage, so the differences are cost and service.