Editing comment to respond to replies in one place instead of individually.
1) The Note 4 is housed inside the Gear VR. Larger battery pack probably won't fit. You will need to carry spare batteries. Possibly the next generation might solve this.
2) I may have missed it, but I didn't see anyway to charge the Note 4 while using the Gear VR. So assuming you do have a charging port, you would need to stop and charge the device. Or carry a spare device to charge your spare battery while you use the Gear VR.
Just to be clear, I am not criticizing the Gear VR. My response was only targeted at the Parent comment's use case. I think it is really cool that Samsung is trying to think out of the box and come up with innovations. Some will stick, some won't. We will see.