High quality, low quantity has definitely been done. Look up some elite runners that do low mileage training for middle distance and apply those principles. I think low mileage probably won't get you as fast in the 5k as you could be, but it should get you close. No idea if it will get you to 17 flat or not, that depends on the person, of course.
I'm not sure what you've done in previous fall/off season training, but even relatively low mileage for cross country will probably make your 200 time slower. You may be surprised with some solid improvements in your 400 and 800 time though, depending how you respond to the increased strength.
Do you have a coach? It would be a wonderful idea to discuss this with your coach, telling him/her your track goals as well and hopefully come up with a plan that is as ideal as possible for both goals.