The camp is hardly 'roughing it' by my memories. Chairs are ALWAYS a good idea, though. You never know where you're going to end up wanting them. There are picnic tables and various other such places on site, though.
Outside of water there is no sustenance type things available on site. This isn't stopping anyone from driving ten minutes into town or fifteen/twenty minutes into New Haven but you should bring food/drink, obviously.
Towels, clothes, toiletries, etc. for showering/hygiene.
Bug spray/sun screen if you're so inclined(everyone always insists they're a must, but I've never had need...your mileage may vary.)
I recommend being prepared for rain. This time of year it's almost a constant for the area, even when the weathermen insist otherwise.