So I received the OTG USB Cable I ordered a while ago, and then realized that even with OTG USB Cable won't work with my Nexus 7 unless I rooted it.
I've been resisting not rooting my Nexus 7 for so long, but finally, the using of thumb drive and a full backup give me enough reason to root it. So I following the instruction here. But it didn't work. I tried again and again using Google Nexus 7 Toolkit 3.2.0 to install Fastboot driver, but it just didn't work (the serial didn't show up).
After being frustrated for a while, (which along the way I learned how to boot to Fastboot Mode) I tried option 3 under Fastboot Mode, which is unlock the bootloader. Turns out that worked out fine, and I also got the device rooted. I tried StickMount and it worked great. All seemed well exception one thing: the device was WIPED FRESH. That means I need to reinstall all the application! This is fine, cause I would like a fresh start so that I can learn how to do backup properly anyway.
I also decided to ONLY rooted Nexus 7 cause I want to experience the difference between using a rooted and a non-rooted phone. That means I will probably continue to use Nexus 7 to do all kind of crazy adventure. That make sense since I need a stable device (my phone) daily use and a development device (one that I can try all kinds of crazy stuff during development).