Totally not a master of anything but using your heart rate to train means that your body is working at the right rate for it rather than at an arbitrary pace imposed on it. Different training sessions should be run at different percentages of maximum heart rate in order to see maximum benefit. For example a recovery run might be at 60% of your maximum while a 5k race will be more like 90-95%. There are rules of thumb to allow you calculate your max heart rate but these are fairly rough and it's simple enough (but not easy!) to calculate it more accurately. Google a maximum heart rate test or someone else here might post a link to wine they've used before.
ATM I've done the meadows half and it was 7 laps if I remember correctly! They run a full marathon at the same time - I think the tedium would end you. What I liked about it was that it was run by students and was really friendly. What I didn't like about it was that it was run by students and the organisation was a bit....haphazard! The half was also about half a mile short. I was doing it as a training run and tagged a couple of miles on to the start and the finish but I might have been a bit shewee-ed off if I'd been aiming for a PB then found that out.
You'll all be devastated to know that not only is it too windy to surf today but its also cloudy. I did my long run yesterday along the shore front watching the sea throw the most spectacular tantrum then went up into the hills and landed on mars. It was spectacular but I managed to sprain the ligaments on the top of my right foot, it's bruised and swollen at any rate. All in all today is a day for reading as many books as possible and going nowhere.