I have spent the entire day on my PC and TF 300 tablet trying to resolve my Flash issues. I have read and reread the page [HOW TO] Get the best browser experience on your tablet and applied the step by step directions carefully many times. I've downloaded different browsers and tried the different steps each time. One forum referenced in the first page, [GUIDE] [HOW-TO] Install Adobe Flash Player on Android 4.1 Jelly Bean was kind of confusing for me so I tried variations of each of the things listed on the page.
I did manage to download a version of Adobe Flash (11.1) and it was an .apk file so I was excited. Then I got a small blue box with a question mark under the "Settings Manager Mobile" tab. It would be wonderful if someone could help me get Flash working on my tablet!!