Hi Aloha,
I love your idea. I'm a children's book illustrator, so this kind of thing is right up my alley. Personally I have always wanted to see something that made preparedness more accessible to children, so I applaud your effort!
Have you examined educational children's books in the store for your target age group? I'm not sure if this project was intended for 5 year olds, but parts of it seem very "wordy" (the checklist) and are probably beyond their comprehension. MDinana has some good comments with how to explain the STOP acronym.
Things like the checklist would do very well with a small image of the item right beside the word. I see you have a photo of the bag and components already, which is helpful. Usually in the industry there would be clean black and white line drawings, color "spots" (small illustrations) or photos throughout the book showing the equipment and how it is worn or used.
If you have the time, check out a few books in the educational market. Workbook-type breakdowns of information, age-appropriate language, lots of illustrations or photos, and presentation are often over-looked by the casual reader but make a huge difference in being understood by the child.
Lastly, please consider changing from that gray background to something lighter (even white) to make the text easier to read and save on your printer ink!
Sorry if my advice just basically puts more work on you. Your project is a very good idea and looks like tons of fun. I don't even have kids and I want to make one too, must be because I make kid's stuff for a living anyway.