Yes you can but it will be quite expensive. For example since you mentioned the Poly if you wanted to stay during value season, check in on a Sunday and check out on a Friday and have a garden view room it would cost you 180 points. At 10/point that is 1800. Plus I am sure the restrictions for renting at a non-DVC resort would be greater than if you were renting at a DVC resort because once these points go to a non DVC resort they can't be converted back.