I'm toying with the idea of doing a local duathlon in the fall (5ish miles running 12 cycling. I haven't run regularly in a couple of years, and have been cycling since august, currently riding nearly 90mins 4 times a week (only long steady efforts so far on the trainer during the winter). I guess I won't really find out until I try and head out for a run, but given my current cycling activities, what would folks say is a good time/distance to start with running?