Re: How much running is too much?
I've been running consistently 20-30 miles a week and only lost a small amount of leg strength (1 short day, 1 medium day, one long day). After a a couple weeks of focusing on my leg strength I hit a front squat PR and my ability to move through WODs in general have significantly improved. Granted though this race season mileage. Normally I'd be putting in 6-10 miles in a week if I was just trying to do cardio.
If you don't pay proper attention to your strength training then yes you can loose mass and strength, but if you make the time and properly fuel yourself you'll be good.