I was typing this 2-3 am. You'll have to exsuce me. I was tired and lazy. I didnt mean to make myself as one of thoes guys at all.
Duuring the Union Army and American terrian is different from Europe. We have hotter climate in the south. In the winter, it doesnt snow in the South. It get down to 50-60's. So, a blanket and tent would be comfortable. Plus big cities are not so big enough to fit two armies. America was still young.
Oh don't worry, as far as I concerned you didn't act like 'one of those guys'.
I know the terrain is different, but that has little to do with it. The Waterloo campaign was fought in the summer, though it wasn't a very hot summer. Whether it was warm, hot, snowy or raining, officers preferred to storage their men in houses then to make camp. For one, it kept them together and easier to collect. Two, there was no need to make camp, which took time and effort.
I think the major problem was indeed too few houses, but I can't believe that they didn't occupy houses that were perfectly available. It makes no sense. What's easier then walking in a house, put your blanket on the ground and sleep?
During the invasion of France, the high concentration of men which all marched on the same road meant that they had the same problem - too few houses, too many men. Add to this the fact that Wellington always gave British troops the honour of marching first, which meant that they were always first in the houses and first at the food, and you can understand why Dutch troops had quite enough of the British, the invasion and war all-together. They were glad to return in December.
