If the trip home is going to be several days, a tent can make a lot of difference. Even if just for basic comfort. It gets old sharing your sleeping bag with bugs. I picked up one of these last year on sale (about half the price it is listed for).
http://www.nemoequipment.com/nemo2010-gogo-tentI thought the inflatable support beam was a bit gimmicky, but it has held up without a problem. It does make the whole thing a lot lighter, and smaller to pack. Its a little smaller than a soccer ball when packed. And you can set it up in a couple of minutes.
Haven't tried it in extremely cold weather. I don't think the air support would hold up too well.