So sorry to hear about your little girl! I had mono as a teenager and missed 3 months of school. The spleen enlargement was tremendous! Younger kids do tend to bounce back more quickly, but when you send her back to school ease her into it. Start with a half day for a week, especially if she has been in bed or in a stroller a lot before she goes back. The physical demands of school - even just sitting up at the desk - all day can be exhausting for someone who has been "gelling" out for a while.
A child on my son's swim team has mono - we are all waiting to see who's next. The mom says that she was told to keep him out of school for a week but resume regular practices/meets as soon as he was without fever. Personally, I think it's nuts. The child looks completely exhausted. The nurse in me wants to go palpate his spleen and check his throat. I'm betting his mom wouldn't appreciate that, though

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As for "cup patrol" - it's not a bad idea to switch to plastic/paper cups and plates for the infected person only. That way there is no confusion.
Good luck. If she likes to read, I bet she would love books on tape. Check out the local library for some good titles. A friend of mine rented a keyboard for her daughter to play on while in bed with mono a couple of years ago. It was a hit! Hope she's feeling better soon!