This app was mentioned in 4 comments, with an average of 2.00 upvotes
Hong Kong doesn't block any of those websites so you'll be fine using HK servers. I spent all of October mostly in China and used the same VPN as you, I switched between HK and Japan (Tokyo) servers.
You literally just press the button in the app to turn the VPN on or off. It's super easy!
I had Lantern installed as a backup which also worked.
Enjoy your trip!
If you're an android user, try Lantern, it is extremely fast and helpful. I personally use it to do the trick.
I use lantern and its great ...
https://play.google.com/store/apps/details?id=org.getlantern.lantern