Interestingly enough, while my kids were always worried about too many pages and too many words, I never noticed them measuring the length of the words themselves.
So how do you trick kids this age into reading hard stuff that expands their vocabularies and their minds and seriously develops their reading skills?
You give them books with a TON of pictures. You make the words seem incidental. You let them pour over the pictures, then read the words aloud with them until they want to grab the book from you and read the words themselves.
Here are a few books that are great for that:
Desk Stories by Kevin O'Malley
Basically a series of hilarious short stories. Lots of great text. But lots of pictures and lots of humor. If your kids like this, try Backpack Stories too!
Sidekicks by Dan Santant
So fun. So very fun.
Bake Sale by Sara Varon
The main characters are a cupcake and an eggplant, and yet, it is a bit dreamy, this book.
Giants Beware by Jorge Aguirre
Watch out, all you fairytale, Disney stereotypes!