I would go gas. I can't imagine running out of electricity on a camping/hunting trip. I can always carry extra gas, but not electricity! Or, I can beg, borrow, or steal gas. Can't do either with electricity!
Regarding the noise, I frequently hunt public land with ATV trails. Many times I've been in the stand and observed deer as ATV's were nearby, or in the distance. Some of them really loud. Depending on terrain, as long as the ATVs were more than 50-75 yards away and out of sight, animals didn't care. Now if you turn the corner and something is standing in the trail, then it's gonna spook.