Another child's book, or level one reading adventure

I had this idea for a kids book the other day and ran the idea over with Preston. Of course, his genius took off with it and soon we had collaberated a pretty good idea. Ok, so I had the title and basic idea and some pictures and he came up with the rest. I will refrain from too much detail as this is a public blog and I am not that stupid. The basic plot involves a little girl, some teeth and detectives. That's about it. So Working thru some drafts, I am having a hard time deciding on what to do. I can do a 15-20 page short story, or go into more detail and explore the little girls detective abilities and short comings and have a pretty compelling story. This would be targeted to the beginer readers (1'st-2nd possible 3rd grade) levels. I would still include some drawings in the book. It would be comparable to the Geronimo Stilton books. I think this girl has potential to investigate many things. This could be fun and a fun way for Joseph to start reading. I'm not focused on doing this for money, so I am just excited to put it together. If money comes I will not complain, but I am excited to see that there are alternative ways to self publish with out spending a fortune, and giving me the oportunity to put it into book form that doesn't involve me manuevering a stapler.