I actually enjoyed that site wrote:
All good runners I know average about 6:30 on their mileage day. Dont be afraid to take 1-2 days per week EASY or cross train, but push every other day. Do longer tempos and 6+ mile runs at around 5:40-5:50 pace. Then hit 400m repeats on the track in around 60-62.
I'm going to have to go ahead and disagree with you on this stuff. I've done a handful of miles under 4:10, and I'm usually more of a 7:00 pace type guy on the easy days. Sure, every so often I get rolling, but in season especially, when you're running two track workouts and a race most weeks, the other days are pretty much just easy running.
To the OP- what's worked for me is plenty of miles, medium-length reps on the track (600-1000m) at ~3k type rhythm and very controlled faster running. The first season I ran 4:10, I was doing tons and tons and tons of hill workouts (stuff like 10x1min uphill at mile intensity with a jog down).
I think it's more important to run hard but controlled sessions, take it pretty easy on the easy days, and keep the miles up in the 70+ range. Since you've noted you're aerobically weak, I'd work on that side of things a lot. You can maintain speed very well just by doing lots of strides, but aerobic improvement can take a little more time.
For helping the endurance side of things, I think it's better to do things like 4mi tempos starting at ~5:30 pace and feeling GREAT, then learning to run faster at that "full of run" feeling over effort. I think 5:50 type miling is enough to wear you out, but not really fast enough to do much good, unless you go for a very long time. A good rule of thumb for a 4mi tempo would be trying to get to the point where your pace/mile is just about 1min slower than your goal mile time. If you want to run 4:09, you'd want to build into a 4mi under 20:40, but, more importantly, feeling quite easy at that pace. You don't want to be gritting your teeth and pushing; you want to be holding back and almost feeling like "I'm not getting everything I can out of this run."
Keep in mind, too, that everyone is different, and for some, those tempos might not come down quite so fast. To be honest, when I ran 4:08 for the first time, I couldn't run faster than 5:15s and stay in the effort range I prescribed above. I didn't let it bug me- I figured 5 sec/mile was "close enough" and never worried about it all that much. Shortly after running 4:08, the tempo came down a lot without the effort changing. Sometimes these things aren't logical.
If you're having trouble with 4mi at 5:30 to start, maybe for your first one, instead of 4mi straight, do 3xmile at 5:30 pace with an 800 in ~3:00 in between each mile. From there, you can work on improving those 800 "rests" at 3:00 to the same pace as the miles and just turning it into a straight tempo. Just remember, for these workouts, pushing harder isn't better. The trick is to get faster, but as a result of fitness.
Lastly, I've always found 400 reps to be overrated. Any jerk can go out and run hard for a minute, take a min break, run hard for a min, etc. I always tried to run ~mile pace as EASILY as possible. I wanted to feel like I was "jogging" at 62s instead of "pressing" to hit 60-61. Obviously, you're not really jogging, but you get what I mean. Also, RUN your rests. If you do 8x400 with a min off, try to jog at least 200m in that minute. I know that seems easy, but believe me, it makes a difference.
Best of luck to you!