50 miles a Week, too much?

I am tempted to give up my dream/goal of running 50 miles a week. I hope it's not because I am scared of hard work or because I am lazy, but I am nervous about over-training and getting injured. My knees have been achy and my right heal is really sore again, I can definitely pin-point the pain, so I am nervous about another stress fracture. So even though it is hard, I am choosing to back away from my obsession with mileage. I will still aim for 40 miles a week, that should be enough as long as I am diligent about cross training. My main goal is to run and stay healthy. Running myself into the ground has no benefit for me if I end up injured. My goal is to get better and better in shape, and that requires me staying healthy in the long run. I sat down with my coach before the summer and he thought 56 miles a week would be a good goal for me in order to run a 24 minute 6k, but I need to be careful, because I am injury prone. I never know how much of my injury prone-ness is mental. But I think at this point in the (off)season I would be best of erring on the side of recovery. Here is my plan of attack (poa) to run injury free
1. Make every run quality. Aim for high mileage, but don't stress as long as I am over 30 miles a week, I am ok.
2. Cross train! This is something I have yet to do this summer. So I am making a commitment to cross train as much as I can, but at least 2 times a week. I can read a book while I bike, watch TV while I elliptical, or cool off in the pool.
3. core, core, core. I really need to do a better job on my core and pks (pillar killers). I am making a commitment to do ten minutes a day of core, mostly planks, pushups and look up some hip strengthening exercises.
4. pks: at least 2-3 times a week
5. lifting: I have never been a big fan of lifting, especially because I struggle creating the calorie deficit necessary to prevent bulking up and I am naturally muscular, NOT your distance runner physique.
6. Stretching: this is another area I have lacked this summer. I am committing to stretch (at least a little) after every run
7. Strides: this past week I have been better at incorporating some short sprints into my run. I am proud because I have added them in the last half mile of my run, the part where I usually slack off/walk. The last stretch of Central park is one of the only parts with hills (even though they're babies!) so it feels good powering up them and I feel so fast on the slight decline. I LOVE the feeling when I am sprinting fast; I feel like I'm flying! So free, so fast, so light.
8. At least twice a week, extended core. Above and beyond my ten minutes a day, twice a week I will do a longer session. Maybe get a pilates or core DVD, some ball work, etc. My "extended" session will be at least 20 minutes. I've read that the elites do 45 minutes of intense core 2-3 times a week, obviously i'm not there, but still, I am capable of lot more than i'm currently doing.
9. 1500 calories a day--It's easy for me to eat less, i get caught up in the exhilarating feeling of hunger. But I need to stop snacking, being honest about how much i'm eating, eating healthy sources of fats, incorporating treats, and eating at least, and hopefully not more, than 1500 calories a day. losing weight will not only help me to feel good, look good, run good, but also it will help prevent injury!
10. Hills: I have largely avoided hills in my runs this summer. This is mostly because my neighborhood is pretty flat, but still there ARE hills, i just haven't gone out of my way to scale them. This will change. From now on, I am going to seek out hills and run up them. I'm not aiming to do a hill workout quite yet (in a couple weeks I'll add a hill day!) but I NEED to do hillier runs. I am lying to myself if I am recording long miles at good paces on only flat streets.

Alright! So there is my ten step plan to run injury free. As I said before, it is hard swallowing a lower mileage. I joined this running website called Running2win.com and all my workouts are posted for my whole team to see, so I would like to impress them, but I need to remind myself that they don't care! Even though it feel like they do, they love me for who I am, they are not going to judge me for a slightly lower mileage. I would be foolish to run more than I can handle and end up injured. My team would much rather have me healthy than recording crazy summer mileage. Not to leave out, that running that high mileage, I run the risk of substituting speed for distance, and as I'm training for the 6k, I would be stupid to neglect speed in order to log long miles.
All that being said, I need to do about 10 miles today to keep on track for 50 miles a week, but I have a race tomorrow and my knees have been hurting. I am going to run at pleasant which is a 5 mile loop, mostly on grass/gravel which might help some of the pounding. Even though this is a long run, I am only going to do one lap and then see how I feel. I am tempted to race myself, and push the pace and see how fast I can round the lake, but I'll save that for another day. I think I will have to do at least 8 miles to count this as a long run, but maybe I could do a long run on Sunday with maren (doubtful, she said she's slow....) or sunday (doubtful, after a race?) well, against my better judgment I am going to play this one by ear. i know that often when I "wing it," I end up slacking. This is where I often struggle. I can see both sides, and I struggle to strike a balance. I can see the benefit of working hard, I mean look at Dan Greeno, he's ALL hard work and that has served him well, but I don't want to overwork and end up injured. So here's my tentative plan:
run around pleasant lake: 5 mile loop, aim for at least 8 slow miles (would I be better off going fast?), no I will keep this one easy, i can do faster workouts later on this summer, and then I will go to the ymca to bike, swim, and/or lift. then extended core workout, lunch, shower, and read at the beach or go to the mall, or bookstore. gonna be a good day as long as I can keep my eyes fixed on Him. That is, afterall, ALL that matters!