Keep in mind this wasn't unoccupied territory. The Massachusett people (or their ancestors) had lived there for thousands of years. I suggest looking up the Woodland Period to find out how people lived and what they ate at that time.
Here's a starting point.
Thanks. The research I'd found previous to this did have it as largely unoccupied. It was talking about the Hopewells just moving east over the Appalachians, but mentioned nothing about any peoples already there.
Not sure if this makes the protag's journey easier or more difficult.
Another thing to keep in mind is that the Columbian Exchange of plants and animals hadn't happened yet. A lot of species that are now considered native to eastern North America, like clover, daisies, dandelions, earthworms and honey bees, wouldn't have been there in 500 AD.
Great! I had a neat little side arc involving honey in my mind. Oh well, maybe I can make it work with maple sap.
Earthworms surprises me.
My problem here is that trying to research, say, what sorts of trees the protag would encounter on that little peninsula he appears on leads me down multiple rabbit holes, none of which will tell me anything unless I already know what to look for.
"Oh, you want to know about white pine? Well, here's a bunch of useless information on white pine that only botanists will have any use for. Oh, want to know if they grow in a spot more specific than 'generally this half of the continent'? Good luck with that!"
I even looked up the Delmater Sanctuary, which is the exact location I need. I can see the thing on the Google Satellite map, and even see the damned trees. Think I can find out what they are, though? Nope. I've found the name of the security guard who watches the trails, I know which trails are in need of clearing, and the name of the guy who's fighting with the town over rights of way along one of the trails. Beyond that, about what grows in the sanctuary itself or why it even is a sanctuary? Nothing.
Anyway, thanks for the help. Barring further info, I think I may have to mush ahead using placeholders and come back later when I've got more time for research.
I envy those movie characters who can find anything, no matte how obscure, on the internet with a few keystrokes and an 'aha!'