Whenever the prophetic chronology of Jehovah's Witnesses is criticized, it begins with their commitment to 607 B.C.E as beginning of the seventy weeks and the relevant archaeological evidence. However, it seems to me that there is an easier way to debate the issue. Why not show them that the so-called day-for-a-year-rule is unwarranted. The society's literature only gives Numbers 14:34 and Ezekiel 4:5,6 as proof of this rule, but we could easily show how this is bogus and how this really originates with the Seventh-Day Adventist tradition.
Their commitment to this rule is just as important as their historical claims, but it's easier to disprove. The problem with debating about 607 B.C.E. and the archaeological is that most of that information is too inaccessible for the average Witness, who is usually not in the position to understand such evidence. I think refuting the day-year rule would be easier and once you see that you can't get 2520 years ending in 1914, that would undermine their need to commit to 607.
What do you think? Don't you think it's easier?