PA is probably different from the rocks here in the west but I probably don't even burn 1 gallon an hour during trail rides.
I'm currently using the stock K5 31 gallon tank and it hasn't been below half full for more than a year, I simply don't use that much fuel even in a couple days of trail riding. I fill it up when I have the chance just to make sure I don't run out.
I'm still leaning towards switching to propane with two 10 gallon tanks, I foresee no problems (I will run a bigger tank on the trailer to fill between trails if needed).