My son and I are hiking about 40 miles of the AT through the Great Smokey Mt. Nat. Park in June. My plan is to wear a good pair of trail runners for comfort instead of boots. I see all these shoes with GTX lining and I want some, but do I need some? Also, I know these are "breathable" but all the experience I have with these is that they actually fall short in the breathability department when compared to non-lined shoes. Are these a necessary piece of equipment or is it another thing to waste money on?