I think it will depend on your grandmother. My grandmother is nearing 80 and lives in New Port Richey, FL. We go visit her almost every year if we can. We went down to see her in May 2000 and she went to Sea World, Epcot, etc., with us. Well, I have been unable to go see her again until 2 months ago. When we went back, she wanted to go to Epcot. We took her and I have to say it was a drastic change from 2000.
She is in good health and has no trouble walking and such but in 2000 she had just as much energy as any of us. We did almost everything at Epcot that year. This year, we were there for 4 hours and she said she couldn't take any more. She was too tired. Honestly, she was ready to go in about an hour, but is too stubborn to say so until she just can't take it any longer. I was a little surprised b/c she still seems like she has a lot of energy to me. I guess waiting in line has just gotten to be more for her than it used to be. I think I would ask your grandmother if she wants to go. If she is like mine, she will tell you no if it's not something she would like to do. Mine always says no to MK and US/IOA!