Summer temperatures

I keep Lily up in my room, on the second floor of our house. We do have air conditioning, but it doesn't get to the second floor very well, so the temperatures get up pretty high sometimes, if it's a hot day. I think it can even get up near 90 sometimes. So I was wondering a few things.
1) Should I consider moving Lily's cage downstairs someplace during the summer, making sure that the air conditioning doesn't get too cool for her?
2) What's the highest comfortable temperature for hedgies?
3) Is there anything I can add to her cage to help her be able to cool off better in hot weather?
4) Should I still use fleece for her liners/strips in her pigloo? Or should I switch to a different, cooler fabric? If so, what do you suggest?
Thanks for any help! I just thought I should ask about this before I end up with an 80 degree day, lol.