Any or all of the following would be a good idea before starting a Pediatric Intern year
1) Read baby 411: Questions and answers about new babies, written for a parent, by Pediatrician. Takes 1-2 days to read and annotate. Pretty much half of my clinic is parroting things from this book.
2) Read toddler 411: Same as above, but ages 1-5.. Takes 1-2 days to read and annotate
3) Make anki flashcards of developmental milestones and spend 10 minutes a day with them. Every time you see a kid start trying to guess his age based on what he is doing
4) Learn the vaccine schedule and routine screening guidelines for Pediatric clinic. Consider doing the CDC modules for vaccines:
https://www2a.cdc.gov/TCEOnline/newmember.asp
Things a really motivated future Resident could do (one of):
1) Read/complete Polin and Yoder's Workbook in Practical Neonatology. This is a case files book for the NICU. Odds are that NICU is going to be one of your hardest rotations, and you will have had either one or no months of education in it prior to starting Intern year. Its a tough read (like it will take 20-30 hours to read through and understand it) but its well worth it, especially if you make flash cards and really drill down on the concepts. If you pair reading it with an MS4 NICU rotation you'll be a suprstar
2) Listen to ICU rounds, by Dr. Jeffery Guy. OK, this is actually a series of lectures for adult ICU, but FWIW I think this is the best summary of ICU care out there. there are 70+ lectures, all half an hour to an hour. You will be much better prepared for worst case non-nicu scenarios if you listen to them. They're on ITunes
3) Complete Cleveland Clinic's program in Pediatric Radiology:
https://www.cchs.net/onlinelearning/cometvs10/pedrad/default.htm
4) Learn EKGs! Read through Dubin, then do 5 problems a day on Wavemaven
5) Learn to accurately describe a rash: read through lookingbill and Marks Principles of Dermatology. Its written for a medical student on a 2 week dermatology rotation, takes 1-2 days to read through.
If by some bizarre chance you get through all of that, you can read Zitellis. If you really want an all subjects Peds textbook that is actually readable as a book, rather than a reference, that's the one I'd recommend. Just going through an old Pediatrics in review every week would also be awesome.
Things I would NOT recommend
1) Peds RAP. I think this is really designed as a review/update for a board certified physician, or at least a senior resident. Don't do it unless you have a long commute and you've finished all of ICU rounds.
2) Nelsons. This is a reference
3) Any Qbank. Its just not that time yet.