quest progression locked - need help

Well, the first thing to keep in mind is that your level is very likely to outpace the quests associated with that level, especially as a newer player. Don't give yourself heartburn over that.
I think I sent Homer to eat at Krusty Burger a good twenty times before the "heavy user" quest started. I don't know if sending him on the task actually helped or if it just killed time until everything was in place, but it's the only suggestion I have for you.