My policy with starting off rps is to make the goals achievable by all characters. A small change from "Samantha (player character) needs to see the queen" to "A member of the party (any player character) needs to see the queen." It's also important to remain in contact with the people spearheading the group to make sure dead ends are avoided.

	And then sometimes you're just unlucky and 80% of your group loses interest.