How far in advance can I prepare a fruit cup? My work used to sell fruit cups that were simply just plastic cups filled with cut fruit pieces, no syrup or anything. I quite liked having a mini fruit salad like that, and would usually buy ones containing pineapple, grapes, apples, and/or strawberries depending on the season. But they don't have them anymore :(

Obviously cut fruit doesn't last very long, even in the fridge. I could probably prep a cup the night before to take with me in the morning. But is there any way I could prepare it on the weekend to use sometime during the week? Do any of the fruits I like freeze well? Are there any fruits that would work better? What if I vacuum-seal the fruit? Can it in syrup like you find at the supermarket?
I would recommend vacuum sealing. I have found that, if done properly, vacuum sealing should remove all of the air and thus prevent the oxidative process that discolors and deteriorates foods

I have tried this with various cut fruits and vegetables including, but not limited to, avocados, apples, onions, tomatoes, etc. and have found that within 2 or 3 days there was no discoloration or deterioration. I can't speak to longer periods of time as I have always used the cut fruits and vegetables within one to three days, but it works well for up to 2 or 3 days.