This series by Todd Strasser is described accurately enough on its Wikipedia page. But the sequence there is only generally correct, not actually accurate.
As a kid reading them, I was confused about the intended sequence, and tried to puzzle it together from internal references to earlier books, but never managed to figure out the whole sequence for sure.
As evidence that the sequence on Wikipedia is incorrect, on page 111 of "Help! I'm Trapped in my Lunch Lady's Body" there is reference to the events of "Help! I'm Trapped in my Camp Counselor's Body" though the latter book supposedly came later.
This page shows a rather different order, with the correct relative sequence of the two books I mentioned, but I'm skeptical it's entirely correct especially since it lists "Help! I'm Trapped in the First Day of Summer Camp" three times, twice with incorrect titles.
Has anyone worked out all the internal references and the correct sequence of the books?
(Note: I may end up self-answering this question, if no one else can point to a definitive sequence backed by all the internal references. It may be one of those questions where nobody cares but me. But I thought it worth checking first, anyway.)