Sounds fun. During the 1750's-1780's upper class Americans drank coffee and tea (though no tea bags yet). They ate a lot of preserved foods so maybe a tiny jar of jam. They played backgammon and dice. You could print off a map of the original 13 colonies. You can also find a photo of "The Compleat Housewife" on Wikipedia. This was the first cookbook published in the US in 1727. You could enclose some cotton balls representing an important cash crop of that time. And a small sample of unbleached cotton muslin fabric that would have been manufactured then as well. and if you were thinking of wooden teeth you would be mistaken. Washington had false teeth made from animal teeth! Gross!
Well, I may put a dollar bill and a quarter in there to show how much we still appreciate and honor his life? I do not know if that would be acceptable since you said life but it seems cool to me. (: Good luck!