While a bit in the weeds, we found the Marriott Towneplace Suites to be a very nice location for a week or so at a time. Does not connect with Mayo main campus, but is only a nice walking block away. Underground parking, low rates, nice complimentary (but presdicatable breakfast), and a caring attitude,
https://www.marriott.com/search/hotelQuickView.mi?propertyId=RSTTM&brandCode=TS&marshaCode=RSTTM
Mayo has pay as you go concierge parking, but we found it easier and less expensive to drop the patient in the drive through (usually a very busy place), and the driver pop the car directly across the street to the pay as you go parking garage.