Can you put up a few very simple decorations. We ended up with our house being set on the foundation on Dec 1 of last year and since it was supposed to only take 3 weeks was in the same predicament ourselves last year.
I put up a few decorations on the entertainment center such as a musical nativity, fiber optic angel, a couple of special gold pine cone candle holders which happened to be the last gift I ever got from my granddad, the gingerbread house my 3 year old daughter made. Christmas eve I hung the stocking on the wall, and placed a small (21-24" tree on a small stand and put the presents on the floor next to the stand. (Not only were we not sure exactly when we would be moving but I had a two small children ages 3.5 and 14 months in a 850 sq ft house)
All my oldest cared about was the stockings and the tree. The nice thing with a small artificial tree is that you can later place it in a bedroom or even a bathroom if your vanity counter is large enough. Stockings on the wall shouldn't be too hard to do especially if you declare that they will be taken down the night of the 28th.
So I would say decorate but just choose one area such as the entertainment center or the fireplace to decorate and keep it simple only using a few very special items that your family particularly enjoys.
Tammy