RE: Okay CDOW - Good Job!
IMHO you've got to have a floorin your tent, otherwise the earth will be the source of massive condensation events, especially when warming the tent up in the morning after its being cold at night and this can lead to your own private indoor "rain" storm.
Consider using a polypro tarp (cheap) held in place with landscaping staples, be careful of your sod cloth when you tack it down.Put rat poison down before you put the floor down as you'll see little critters crawling around under the tarp and they will chew on everything and keep some folks awake at night.
Carpets are nice to have next to your cot for when your feet hit the ground; however, they are heavy, bulky, and get nasty. I would only put them on top of a tarp not directly on the earth.