With pads, clothes, and a bag you will be fine. The pad will prevent heat loss to the bottom( that's why people use them in tents, it ain't for comfort) and your sleeping bag will work fine as long as its rated for that temp.
"We do not go to the green woods and crystal waters to rough it, we go to smooth it."- G. W. Sears
My forum name is Fish<><; I'm in the navy; and I hate sleeping on the ground. If I didn't need ground to walk on or measure resistance to, I think I could happily give it up.