Generally, it is impossible to tell in advance how likely you are to get bumped. The best thing to do is be the first one to Volunteer at each station. Once you get into connecting flights there are more variables than how many seats are sold. You have the inbound passengers on any number of flgihts that could be delayed for any number of reasons.

Upgrade Me's, first point is very valid in that none of your Flights are on NW metal. It may have been booked with NW miles, but none of your flights are on NW metal. NW is very good at estimating how many people will show up and seem to bump less than other airlines.

I would suggest you do a search on the CO boards and see past history for bumps. I don't think posting it on the CO forum would do you much good either, because there are so many variables that not even the airline can predict in advance how many people will show up.