Do you know what the other stops are serving? That might give everyone a "starting point" on helping you come up with a dessert or variety of desserts.
Yeah, have me over. Anything Chocolate is a big hit. Don't forget the coffee & after dinner drinks. A chocolate fountain with various dipping treats would look elegant & pretty when your guests arrive. This way your guests can have a little or a lot depending on how full they are. Strawberries, brownies, marshmallows are great dippers. Have fun at your party.
Does the party have a theme? The house hopping parties I've been to have had themes - traditional (this was fun because it was many different traditions), mexican, italian, etc.
Are you looking for quick and easy, make ahead, elegant?