The 5BBT does not have a century option. 42 miles, or shorter if you bail, and that's it. Otherwise those are all pretty good suggestions. As an option, cross the GWB and loop around to what we all call River Road, but is officially Henry Hudson Parkway. This is a lightly trafficked road right along the river on the NJ side of the bridge. There are 2 decent climbs too, one in the middle, and then the final climb out at the north end.