The amount that you should be running now is a function of how much you ran in the past.
Not the race you're training for.
If you ran in college, you already put good miles in and can focus on swimming and biking and should just focus on maintaining run fitness. If you don't have a running background, you simply need to be running more than you were before. Averaged 20mpw last year? Shoot for 30 this year. Averaged 40mpw last year? Shoot for 50 this year. Adding about 10mpw to your weekly average over each year is a reasonable progression. But if you're fit, strong, and not fat - you can probably afford to go from 30 to 50-60mpw in a single year. High school and college kids do it all the time. The off season is a good time to really focus on building running volume.
The bulk of your running should be fairly easy. Tempos, occasional fartleks, hilly runs, and progressive long runs are the meat and potatoes. Track work not really necessary. If you're going to do bricks (jury is out on these), keep them short. I like to do a 1-2 mile brick at threshold pace after my long ride. More for coordination and mental prep than any expected physiological benefit.
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