I didn't go to camp (virtually non-existant in the UK) but I spent much of my summer holiday with my Grandparents in London.
Despite the fact my sister was older then me and also used to staying with my Grandparents, the one year I spent a week at Brownie camp she got so homesick without me that my parents had to bring her home (and juggle shift work schedules to do so).
So the one piece of advice I'd give is let Lil Pete know she
might be homesick, but if she is, it won't last. Don't make a big deal out of it (obviously!) but as long as she can accept she'll miss you it won't become the sum of her experience.
Bet she'll love it
