The 800 is one of the most fascinating races in there is a wide divergency of ways to try and approach training for it at a high level with no one clear cut way proven superior. It is a "tween'er" distance. Somewhere between sprint and distance. I've seen runners successful at the distance with mileage as low as 20 per week and as high as 80-100 per week.
I think a lot depends on the strengths and background of the individual training for the event.
I have a few friends who coach the event at a high level who like this base model.
2 Days Cycle:
Day 1 AM: 3 miles easy PM: 5-6 miles easy plus strength training session
Day 2 AM: 3 miles easy PM: Stress Workout - what is done in the stress workout depends on the time of year