Re: RPGs for Dummies: Getting 5 - 8 year olds into the hobby
As far as plots go. A lot of plots for young children revolve around getting some item to stop some evil force. Getting the item allows someone to banish or stop some evil power from winning.
Suggestions would be, make opponents be more clearly fall into one of a few categories of characters.
1. Clearly Evil and inhuman (these, the heroes may actually try to destroy them)
2. Misguided (these people, the heroes should try to rescue from deceit)
3. Animals/creatures (these are not really sentient, so depending on the kids maturity, they might see opportunities to subdue them, or otherwise may be able to understand potential loss)
4. Nonliving... (constructions, robots, magical manifestations, traps, etc) Undead (might fall into this or the first category, but also might be disturbing for some children, so that might be weighed in your decisions)
Keep in mind that you can probably use some form of rules to impart subdual damage for those whom it would make sense to insure a humane defeat. Also, you can use damage thresholds to reflect a point where rather than dying, the creatures turn tail and flee.
Ideally, I'd have them gather things, in scenes, and then certain obstacles, if they have gathered the required items, have it be an automatic success to proceed through... if they failed to get something, let them make some kind of 'skill' roll or such, with modifiers based on what they have gathered, plus some bonus if they can come up with some problem-solving ideas to help them. Stressing the action of problem solving, being more important than the solution being that good an idea.
If the heroes fail, you can have them be captured, and have someone unexpected help them to escape, potentially at a cost to the helpers. (to help encourage them not to simply rely on getting captured and have someone help them) It isn't uncommon in stories, for someone to help the heroes escape, but get caught, and have anything from becoming imprisoned, hurt, or even died helping the heroes return to their quest.
Well anyway, that was some quick thoughts.