Fair warning for everyone:
This adventure starts in medias res so you won't have time for last minute shopping between the time you get told about the mission and when you depart (you get your faction missions and a description of the destination after you accept the offer to go). There are some mundane supplies available at the site (food, shelter, ropes, light sources, etc.) but nothing special.
To paraphrase the theme of the adventure in just four words, I'd call it:
"Archaeological Dig Gone Wrong"
That doesn't mean you can't do purchasing before the game starts that will be accounted for on this chronicle. Feel free to fill your boots on that front, just no retconning once you're on the road.