Make sure to use a rimmed baking sheet or pan as the pumpkin can get quite weepy during the baking process. Lining it with either foil or parchment paper will aid in cleanup.
I have made this using a higher temperature (425 degrees) during the latter portion of the baking -which enabled me to bake cornbread at the same time - and had great success. Just lightly cover the top of the pumpkin with foil to prevent browning/scorching if needed.
This meal can be made vegetarian by using a vegetable based soup, omitting the meat and adding additional vegetables - eggplant, celery, grated carrots, etc. The vegetables will need to be sweated or sauteed before adding - to make sure that the filling isn't too moist.