Thanks! I'll have to consider doing a test like you describe downthread sometime. Most of my biking is just getting home from work. And, well, that is only 20 minutes on the bike. Large hill, but still just 20 minutes.
The canonical running test is to run an all out 5K. You can then derive pretty simple training paces based on tables. See: Daniels Running Formula. Or any number of training calculators on the Internet. A 5K is a very good measure if your overall running fitness and a pretty good predictor of race performance from 10k to Marathon. It helps you set up good training paces. Then it just comes down to volume. When you find your HR creeping out of zone don't be ashamed to walk to chill it out.
You can definitely go out too hard in a 5K, it isn't a 400, 800, or 1600M effort, but if you aren't hurting and questioning your life choices the last mile you weren't going hard enough :)