I found these videos helpful to me to get the feel of Mayo before I went there as a patient. You can see the subway levels. I had to pick a hotel without ever being there my first time and I picked one close enough for me to walk (but not the nicest hotel). Some of the closer ones cost more than the ones farther away with shuttle service. Last time I stayed at the Hampton Inn, and they have their own shuttle service to the Gonda building and St Mary's Hospital. They run early and you can make a reservation for the shuttle ahead of time to guarantee a space.
The Gonda and Mayo buildings are connected on every floor, but pay attention to the sign for the elevators because some stop on the top half floors of the building and the other set stops on the lower half of the building's floors only. The waiting areas are beautiful with lots of artwork, and computers you can use. Make sure you see the Chihuly glass chandeliers over a staircase in the Gonda building (near the information desk) . They are spectacular.
You might be able to get through your appointments earlier, because you can be a "checker" or standby, and if they have an earlier opening for testing, they can take you. You may not need to stay all week if you don't have appointments, sometimes they can reschedule those too. It just depends on what they are. In the atrium of the Gonda building is a piano, and it's nice to listen to people playing it.
I'm sorry that the hotel staff were not very courteous, but don't let them take away your enjoyment of Mayo. I think you will love it there. I suggest when you arrive if it is early enough, go tour the buildings and get the feel of it. It's a beautiful place and I've enjoyed talking with other patients there, and all of my medical providers were very nice. They are so efficient too. I've never experienced that level of excellent care anywhere else. I had surgery at St. Mary's and wanted to know what the hospital looked like ahead of time, but couldn't find much before I went. If you want to see my pictures of St. Mary's, I can send you a link to my facebook page. There is also the recent Ken Burns documentary about Mayo that covers all the 3 campuses. If you have time, the historic Plummer building is right across from the Gonda/Mayo buildings and you can see the original offices of the Mayo brothers who were the sons of the founder that are on the 2nd floor and historic things like old surgical gowns and a microscope, and the Nobel prize for the discovery of cortizone.
I was out helping my mom today who is in a wheelchair and driving her to her doctors appointment, so I understand your needs. You've got a lot of spirit to go by yourself, and you'll be fine. I went by myself last time which was very special as I had a delivery for my surgeon. Go ahead and check that out (and you'll see a picture of pretty stain glass at St. Mary's) on the Jan 9th blog at sharing.mayoclinic.org
Let me know if I can answer any more questions.