Keep control, keep it moving:) I found school visits nerve wracking (Imagine, a grown woman made nervous as heck by a group of 5 year olds, haha) and just not my thing, so only can handle doing a couple a year, but have a few suggestions.
No matter what, keep it moving. Other wise you'll be listening to THEIR stories till the 45 minutes is up. You mention dog, and suddenly every hand is up, to tell you they have a dog too, it's name is "Charlie"/ "Ben" /"Fluffy", it's black, it's brown, it's green, and it eats poop (and every one laughs in the group) etc...Just say, that's nice and move on, quick!:) The teachers are almost always GREAT and they work on the sidelines, to control the "mob mentalitly"
Ask that the teachers make sure the children are familiar with your book. After they read it to the class, the teacher might also ask the kids to do their own drawing of one of the books characters. They then have something to show and even give to you when you visit (they love doing that)
I'm not sure if your the Illustrator? They LOVE if you draw for them, so if you are, ask the school supply and easel and pad of paper. I really hope the projector works for you because the iPad screen will not be large enough for the group to see the pictures and they will knock each other down trying to get close enough to see.
The stick puppets are great, they will LOVE them!
With grade 1, the questions are truly QUESTIONS. With the little guys, "do you have a question" seems to most often result in them telling you about something in their lives, related or not, to the book:) The only true question I get asked at least once during every visit, from every grade, is...
"how much money do you make"?