Appreacite the response, JBloggs. I didn't really know what GeckoOS was/is, hence my problem.
All is working now. GH3 Custom Rock Band is working perfect. I assume Gh1/2/80's will work too.
Got it working by installing the homebrew channel via twilight hack. Then running RegionFree through the homebrew channel and loading the disc.
Step by step, in-case you are me 24 hours ago
1) Use twilight hack to install the homebrew channel
2) Load up RegionFree onto an SD card to be run through homebrew channel
3) Run RegionFree from homebrew channel, follow directions to run disc
I found this guide to help me out. It does NOT include the homebrew channel steps, instead it makes you do the long way of using the twilight hack each and every time you want to play the game. (Twilight hack lets you run RegionFree which is what lets you play the game.)
[Only Registered Users Can See Links. Click Here To Register]
So my only change was installing the homebrew channel instead of running regionfree.