In hilly terrain, low areas near lakes and rivers will be more damp and buggy, Hill tops are more likely to have higher winds but fewer bugs. If there is no wind and lots of bugs up the hills then at least the ground and wood should be dry. I prefer somewhere in the middle. The hill could even help block wind. If you have a hammock and fly then anyone of these locations would be a great place to camp. However, I just came back this morning from a full wilderness survival weekend in northern WI with lows in the 20's. with less daylight and no bugs around I built a brush shelter near the water but had to go quite a distance for a good supply of dry firewood.