Pumpkin is a winter squash so other winter squashes such as butternut, crookneck, and hubbard can be substituted for Pumpkin in recipes. Whichever of the winter squashes you choose, prepare as if you were using Pumpkin.
Since it is difficult to remove the skin from Pumpkin and most recipes call for puree, cutting the Pumpkin in half, removing the seeds, baking covered in a small amount of water until tender, and then scooping the pulp out is the easiest way to prepare Pumpkin for the various recipes.