Alpkit Gamma is more than adequate for unlit country lanes.
It would be fine for virtually all off-road running too.
I might well try out the tip about on the waist. My problem is that when I breathe out when cold (which it tends to be in winter when I run in the dark) I get reflection back off the condensed breath if I wear it on my head.
I have the LED Lenser and like it, but if buying again I'd get the Alpkit as I think you get much better bang for your buck, and as the Alpkit Gamma is plenty bright enough for me the extra £20 is wasted. Also the very low power option is better for use in a tent - the LED is too bright even on lowest power.
So long as it doesn't cause you to overtrain, any aerobic exercise on days when you are not running will improve your conditioning and your running. If you have specific weaknesses then core work/stretching etc. will help your running.
However as a general rule, fitness is specific, and therefore if you want to be as good as possible at running, then running should make up the vast majority of your training. Haile and Mo do not go out for 100 mile bike rides or play Sunday league footie etc.
There are no rights and wrongs really Jason - just experiment and wear what feels comfortable to you. I often turn up at my running club in long sleeved T-shirt and shorts, but with serious gloves on, yet my mate turns up with leggings and several layers on top, but always has bare hands!
A useful rule of thumb is that you should be a little chilly for the first mile or two.
Personally I never wear a jacket when running - in my experience they just can't cope with the amount of condensation generated. I'd rather be wet with clean rain than my own sweat. I prefer to think about keeping the wind off, as the real danger of rain is getting cold in the wind, and for that I love my windproof gilet.
You can get waerproof trail shoes, but they are heavier and as has been said once water comes in the top it stays there. Having had a waterprof pair of trail shoes I will never buy any again and much prefer the "easy in, easy out" approach to water.
I remember running in the North Staffs League back in the early late 80's - great days!