According to most reputable kashrus agencies, plain coffee is not a problem anywhere. Sugar is not a problem as it doesnt require hashgocha. Milk, if you dont keep CY, is ok anywhere in the USA / Canada. As for flavored coffee, I believe all DD flavors are kosher anyway.
Remember, the stuff behind the counter is NOT necessarily the stuff for sale in front of the counter. The bagged coffee at Wawa is not packed the same as the coffee used behind the counter.