Iron, mixing in with cycling/triathlons is a different scenario. However, I'm sure if you speak to your fast peers, they'll either tell you they train like dogs, or are just especially blessed. If your focus is to truly do the fastest 5k you can, you certainly won't do it off tiny mileage.
I'm certain that you'd get nicely under your current 5k pb simply upping the easy paced mileage each week for a couple of months without any specific 5k stuff. It increases your base, and gives you more support to run faster. .
One of the fastest runners I ever spoke to told me that I "hadn't even started training yet", when I told him I did 30miles a week. I'll always remember that.
Ric, i think any of us "Guts" problems types wondered about why it happened before. I thought like you perhaps the intensity was too high. Then you realise the intensity in racing is always higher,and never a problem there, so it's simply a nutrition/timing thing.
Good luck to any TVXCers. With Gosport next week, I'm swerving it. It did feel odd in 2010 doing a XC then having a half the next week, so will be pleased to finish the half and then think xcs.
Edited: 10/11/2012 at 10:12