In my kids' campaign I'm really not letting them have access to the books.
I've printed out the equipment charts and such. This is mostly so they don't get overwhelmed with info, but also to let them not have any preconceptions about what is possible.
I am also thinking of giving them a cut down version of the ASSH character sheet. At the moment they have the full-on detailed one. All I'm mostly thinking of doing is just trying to make it easier for them to see the important stuff. Like ability bonuses, Save mods, weapon damage, etc.
I'm only doing ASSH because I think they can handle the additional complexity as compared to Basic D&D. I'm keeping some of the ASSH complexity at bay but not much.
The real trick is to describe things they have no experience with. Like dead bodies. I described the interior of the "metal box on strange wheels" (APC) as smelling of rotten meat, which they have smelled. I also had the girl run a con test to see if she threw up (I think they liked that). The boy has read a bit more than her but only by like 2 years. They are voracious readers so they'll have book knowledge of things but no real experience of things.
I'll try to use this thread to drop ideas I have and any ideas others might be having with their games with their kids.
Oh, my boy is 10yo and my girl is 8yo. Both are fairly bright for their age I think. What parent doesn't? ;-)