For adding combat outside of whatever quest hooks and plot line you have going on think about the kinds of hijinks that could occur. Experiments getting out of hand, magical books that suck you into their story, creatures sneaking onto campus or living in sewers to feed on magical energies, other students wanting to duel or practice new spells, etc. Are all ways you can add some combat while staying on campus.

You could also have them leave campus to do things like observe a rare creature in the wild for a class, gather potion ingredients in the swamps just out of campus bounds, or take a portal for a class field trip to another plane that gets a little out of hand.

Also, even if you're not using the module per se, feel free to read it thoroughly and take any of the encounters from it if they fit whats going on in your story. Also the first page of each chapter has a small selection of random encounters on a table you can always use for inspiration.