I'd like to see some definite numbers on number of votes versus number of registered voters and the number of registered voters versus the voting age population, region by region. Another thing to find out are your chances of getting a provisional (or normal?) ballot if it's not established at the precinct that you are eligible.
Ohio has posted the number of provisional ballots, by County. It mirrors the regular ballots pretty well. That is, the # of provisionals is about 2-4% of the number of regular. A bit higher in cities and student areas, lower in rural areas, but not by much.