update: I'm sitting at around 90 pretty comfortably now, can get up to 100 for 15-20 min bursts but 90 is more sustainable. As a foot note, I don't have a cadence sensor or watt meter on my bike, just on my indoor trainer so I'm making some assumptions each time i'm on the road but so far its been pretty simple to get a feel for what 90 feels like vs 100 rpm.

Also - JRonaTrek, I'm less concerned about killing my legs at the moment than I am about speed. Bike speed is way down compared to the quick guys in my age group. Comes with being heavy too I guess.