I like the general backdrop of the 35 miles per week consistently through the winter. I would structure it in the following way once you have built up over the first 6 weeks:
I was a 2:04 half miler last year as a freshman in HS..This year I am looking to run 1:57/8 and I think if i have the proper training I can get there (HS coach isnt anything special).
I just finished my xc season today (consistent 18s all year) and will be taking 10 days off and will resume running on Nov. 27. I was thinking of building up my base to 30-35 mpw throught december and january, but I am unsure of when I should start to go back on the track and what workouts I should run.
My first official team practice for track is February 2 and I would be looking to peak for regionals/possibly states the first week in May. any help is greatly appreciated!
M - 6
Tu - 2
W - 6
Fri - 6
Sat - off
Sun - 10
Get the long run in. Also just used to tieing the shoelaces everyday. Some of those "2 mile" days might be just warming up for plyos or weights, but your legs get flushed out everyday.
I would actually not go on the track before February if you are only 15, not running indoors, still growing, and looking to run the 800m. I would take advantage of your legs gaining a ton of power, and really work on your explosive strength all winter long. On the days with only 2 miles I would consider either weights and plyos....really work and measure your vertical leap as a measure. Between Dec to Feb at your age you should be able to improve it 4-6 inches. Just imagine adding 4 inches to your stride in an 800m -- 150 strides in that race, add 600 inches which is 50 feet or 16 meters....and that just on just throwing your legs out in front of one another! Then add on better conditioning and strength and you should be able to drop the 6-7 seconds you are looking for.
You can find a bunch of good weight and plyo routines in this thread and in others...